(CNN) Arriving in terror-shaken Europe Tuesday , President Donald Trump confronts in real time the threats that have underpinned his agenda as he travels abroad for the first time, his message meeting reality on a continent still deeply skeptical of his motivations.

"This is what I've spent these last few days talking about during my trip oversees," Trump said Tuesday as he stood aside Mahmoud Abbas, president of the Palestinian Authority, after talks in Bethlehem. "Our society can have no tolerance for this continuation of bloodshed, we cannot stand a moment longer for the slaughter of innocent citizens."

"I won't call them monsters because they would like that term. I will call them losers from now on because that is what they are: losers," Trump said, a line bearing Trump's hallmark rhetorical style that a senior White House official said he wrote himself Tuesday morning from his room at the King David Hotel near Jerusalem's Old City.

Trump's message on combating terror was largely well-received in the Middle East, where leaders have long sought firmer security commitments from the United States. But there remained few specifics in his plan to combat terrorist ideologies, and some aspects of Trump's stated strategy to combat terrorism appear to contradict some his own administration's actions.

Anti-terror plans

Trump's plan as laid out over the weekend in Saudi Arabia relies primarily on soft power: applying pressure on foreign governments to restrict terrorist financing and better monitor online extremism. But his proposed budget, the full version of which was released Tuesday, delivers drastic cuts to the State Department, the agency responsible for coordinating such initiatives with foreign governments.

The President has proposed dramatically increasing military spending. But in Saudi Arabia, Trump did not lay out a military strategy against ISIS, nor did he make in-depth mention of the current US military efforts against the group, which are augmented by support from Gulf nations.

Trump's administration has been reviewing plans to go after Islamic State in Iraq and Syria, and said during a meeting with the Emir of Kuwait this week that he planned a news conference in two weeks' time to announce what progress his administration has made against the terror group.

"We're doing very well in the fight against ISIS," Trump said at the beginning of the meeting, one in a string of short talks with Arab leaders ahead of his major address in Riyadh. "Tremendous progress has been made. And will continue to be made."

The promise of a news conference to address ISIS, however, has been a long-running feature of Trump's administration that has yet to materialize.

As he departs the region for Europe, Trump will find himself confronted with leaders vastly more skeptical of his agenda than the Arab or Israeli officials he consulted on the first half of his foreign swing.

His professed willingness to scrap longstanding tenets of transatlantic ties has fostered deep unease on the continent toward Trump, even as pragmatic elected officials here work to foster relationships with him. Simmering anxieties after homespun terror attacks in Brussels, Paris, and Nice, France, however, have helped fuel right-wing, anti-immigration parties in Europe that have aligned themselves with Trump, a political upheaval that's caused heartburn for the continent's establishment.

JUST WATCHED What's the point of NATO? Replay More Videos ... MUST WATCH What's the point of NATO? 01:23

NATO focus on terrorism

Anxieties over homegrown terror are now expected to feature heavily at talks at NATO headquarters in Brussels, where Trump will attend a truncated meeting of leaders on Thursday. The matter will also arise when Trump touches down on Sicily at the end of the week to attend his first G7 summit.

British Prime Minister Theresa May, who spoke with Trump Tuesday after the Manchester attack, is expected to attend both gatherings.

European officials say they are looking for Trump to more fully articulate what has remained a purposely ambiguous agenda, including his view of NATO. Trump has recently taken credit for shifting NATO's focus toward terrorism, despite the group's decade-and-a-half long engagement in Afghanistan, and say he's committed to bolstering the group by pressing member states to increase military spending.

But when it comes to Trump and NATO, uncertainty remains. Trump deemed the military collective outdated on the campaign trail, and while he's softened his stance since taking office, his ultimate goals remain unclear. This week, a senior US administration official told European reporters that Trump has not ruled out withdrawing from the group.

Photos: President Trump's first foreign trip President Donald Trump and first lady Melania Trump board Air Force One on Saturday, May, 27, 2017, at Naval Air Station Sigonella in Italy. They were headed back to the United States after a nine-day trip to the Middle East and Europe. Hide Caption 1 of 69 Photos: President Trump's first foreign trip President Trump greets people on May 27, after speaking to US troops at Naval Air Station Sigonella. Hide Caption 2 of 69 Photos: President Trump's first foreign trip President Trump addresses US troops and their families on May 27, at the Sigonella Naval Air Station. Hide Caption 3 of 69 Photos: President Trump's first foreign trip President Trump and first lady Melania Trump arrive on May 27, to address US military personnel and families at Naval Air Station Sigonella. Hide Caption 4 of 69 Photos: President Trump's first foreign trip Leaders of the G-7 and some African nations pose for a photo on May 27, on the second day of the G-7 summit in Taormina, Italy. Hide Caption 5 of 69 Photos: President Trump's first foreign trip President Trump gestures on May 27, during a G-7 session. Hide Caption 6 of 69 Photos: President Trump's first foreign trip President Donald Trump and his wife, Melania, arrive for a concert of the La Scala Philharmonic Orchestra while in Taormina, Italy, on Friday, May 26. The Trumps are in Italy for a two-day G-7 summit. Hide Caption 7 of 69 Photos: President Trump's first foreign trip Trump and other leaders pose for a group photo at the G-7 summit on May 26. From left are European Council President Donald Tusk, Canadian Prime Minister Justin Trudeau, German Chancellor Angela Merkel, Trump, Italian Prime Minister Paolo Gentiloni, French President Emmanuel Macron, Japanese Prime Minister Shinzo Abe, British Prime Minister Theresa May and European Commission President Jean-Claude Juncker. Hide Caption 8 of 69 Photos: President Trump's first foreign trip Trump and Trudeau walk together after the group photo. Hide Caption 9 of 69 Photos: President Trump's first foreign trip G-7 leaders congregate during a walking tour on May 26. Hide Caption 10 of 69 Photos: President Trump's first foreign trip Trump embraces new French President Emmanuel Macron on May 26. Hide Caption 11 of 69 Photos: President Trump's first foreign trip The leaders watch a French air squadron. Hide Caption 12 of 69 Photos: President Trump's first foreign trip Melania Trump arrives at the City Hall in Catania, Italy, on May 26. She was wearing a $51,500 Dolce & Gabbana jacket as she met with other spouses of G-7 leaders. Hide Caption 13 of 69 Photos: President Trump's first foreign trip Trump shakes hands with Macron in Brussels, Belgium, on Thursday, May 25. They were attending a NATO summit as the alliance officially opened a new $1 billion headquarters. Hide Caption 14 of 69 Photos: President Trump's first foreign trip Trump stands with other world leaders during a NATO photo shoot on May 25. Hide Caption 15 of 69 Photos: President Trump's first foreign trip Trump speaks with British Prime Minister Theresa May during a working dinner at NATO headquarters. Hide Caption 16 of 69 Photos: President Trump's first foreign trip Trump stands next to German Chancellor Angela Merkel at the NATO summit. Hide Caption 17 of 69 Photos: President Trump's first foreign trip Melania Trump visits the Magritte Museum in Brussels with Amelie Derbaudrenghien, partner of Belgian Prime Minister Charles Michel. Hide Caption 18 of 69 Photos: President Trump's first foreign trip A girl takes a selfie with Melania Trump at a children's hospital in Brussels on May 25. Hide Caption 19 of 69 Photos: President Trump's first foreign trip Trump meets with Macron in Brussels. Hide Caption 20 of 69 Photos: President Trump's first foreign trip Trump walks with European Council President Donald Tusk, center, and European Commission President Jean-Claude Juncker, right, after they met at the European Council in Brussels on May 25. Hide Caption 21 of 69 Photos: President Trump's first foreign trip Trump, third from right, attends a meeting with leaders at the European Council. Hide Caption 22 of 69 Photos: President Trump's first foreign trip Trump speaks with King Philippe of Belgium as Queen Mathilde and Melania Trump chat during a reception at the Royal Palace in Brussels on Wednesday, May 24. Hide Caption 23 of 69 Photos: President Trump's first foreign trip Tusk talks to Trump as he welcomes him in Brussels. Hide Caption 24 of 69 Photos: President Trump's first foreign trip Trump stands with Belgian Prime Minister Charles Michel while the national anthem is played during Trump's arrival in Belgium on May 24. Hide Caption 25 of 69 Photos: President Trump's first foreign trip Protesters in Brussels demonstrate with effigies of Trump and Michel on May 24. Hide Caption 26 of 69 Photos: President Trump's first foreign trip Trump shakes hands with Italian President Sergio Mattarella in Rome on May 24. Hide Caption 27 of 69 Photos: President Trump's first foreign trip Pope Francis stands with Trump and his family during a private audience at the Vatican on May 24. Joining the President, from left, are Trump's son-in-law, White House senior adviser Jared Kushner; Trump's daughter and adviser Ivanka Trump; and first lady Melania Trump. Hide Caption 28 of 69 Photos: President Trump's first foreign trip Trump and the Pope exchange gifts. Trump presented the Pope with a first-edition set of Martin Luther King's writings. The Pope gave Trump an olive-tree medal that the Pope said symbolizes peace. Hide Caption 29 of 69 Photos: President Trump's first foreign trip Trump and his wife look at the ceilings of the Sistine Chapel. Hide Caption 30 of 69 Photos: President Trump's first foreign trip Trump speaks to reporters in Rome during a meeting with Italian Prime Minister Paolo Gentiloni, right, on May 24. Hide Caption 31 of 69 Photos: President Trump's first foreign trip The first lady visits a pediatric hospital in Vatican City on May 24. Hide Caption 32 of 69 Photos: President Trump's first foreign trip Melania Trump arrives at the Vatican on May 24. With Vatican protocol in mind, she wore a black veil and long-sleeved black dress draped down to her calf. Ivanka Trump wore a similar outfit with a larger veil. Hide Caption 33 of 69 Photos: President Trump's first foreign trip President Trump and Israeli Prime Minister Benjamin Netanyahu wave at the Israel Museum in Jerusalem on Tuesday, May 23. Trump gave a speech there, reaffirming his country's commitment to Israel while also holding up Judaism's historical ties to the United States. Hide Caption 34 of 69 Photos: President Trump's first foreign trip People take pictures of the message Trump wrote at Yad Vashem, the Holocaust memorial in Jerusalem, on May 23. Hide Caption 35 of 69 Photos: President Trump's first foreign trip With the help of US Marines, Trump and his wife lay a wreath at Yad Vashem. Hide Caption 36 of 69 Photos: President Trump's first foreign trip Trump meets with Mahmoud Abbas, the President of the Palestinian Authority, on May 23. Trump met with Israeli leaders the day before and said he believes both sides "are ready to reach for peace." Hide Caption 37 of 69 Photos: President Trump's first foreign trip A Palestinian security official takes position before the arrival of Trump's convoy in Bethlehem, West Bank. Hide Caption 38 of 69 Photos: President Trump's first foreign trip Israeli and American activists hold signs Monday, May 22, during an anti-Trump protest next to the US embassy in Tel Aviv, Israel. Hide Caption 39 of 69 Photos: President Trump's first foreign trip Melania Trump and Israeli first lady Sara Netanyahu speak to children during their visit to the Hadassah hospital in Jerusalem on May 22. Hide Caption 40 of 69 Photos: President Trump's first foreign trip Trump talks to reporters as he meets with Israeli Prime Minister Benjamin Netanyahu on May 22. Trump sought to rebut claims that he damaged Israeli intelligence capabilities by revealing highly classified information to Russian operatives earlier this month. "Just so you understand, I never mentioned the word or the name Israel," Trump told reporters as he began the second leg of his first foreign tour. Hide Caption 41 of 69 Photos: President Trump's first foreign trip Trump touches the Western Wall, Judaism's holiest prayer site, while in Jerusalem on May 22. Trump became the first sitting US president to visit the wall. Hide Caption 42 of 69 Photos: President Trump's first foreign trip Trump stands in the Western Wall plaza. To his left, in black, is Shmuel Rabinowitz, the rabbi of the Western Wall. Hide Caption 43 of 69 Photos: President Trump's first foreign trip First lady Melania Trump, in white, visits the Western Wall. At far left is Ivanka Trump. Hide Caption 44 of 69 Photos: President Trump's first foreign trip The President and first lady plant a tree in Jerusalem with Israeli President Reuven Rivlin. Hide Caption 45 of 69 Photos: President Trump's first foreign trip Trump is welcomed by Netanyahu upon arriving in Tel Aviv on May 22. Trump started his trip with two days in Saudi Arabia. Hide Caption 46 of 69 Photos: President Trump's first foreign trip On the way to Tel Aviv, US Secretary of State Rex Tillerson speaks with reporters aboard Air Force One. Hide Caption 47 of 69 Photos: President Trump's first foreign trip While in Riyadh, Saudi Arabia, Trump attends the inauguration ceremony for the Global Center for Combating Extremist Ideology. Joining him here are Saudi King Salman bin Abdulaziz Al Saud, center, and Egyptian President Abdel Fattah el-Sisi, left. Hide Caption 48 of 69 Photos: President Trump's first foreign trip Trump speaks in Riyadh during the Arab Islamic American Summit on Sunday, May 21. Trump looked to make it clear that the United States is not at war with Islam. "This is not a battle between different faiths, different sects or different civilizations," he said. "This is a battle between barbaric criminals who seek to obliterate human life, and decent people of all religions who seek to protect it. This is a battle between good and evil." Hide Caption 49 of 69 Photos: President Trump's first foreign trip Trump sits at the summit, which included leaders from 55 Muslim-majority countries. He urged them to do more to eradicate terrorist groups that claim the mantle of Islam. "We can only overcome this evil if the forces of good are united and strong and if everyone in this room does their fair share and fulfills their part of the burden," Trump said. "Muslim-majority countries must take the lead in stamping out radicalization." Hide Caption 50 of 69 Photos: President Trump's first foreign trip Trump poses with other leaders at the Arab Islamic American Summit. Hide Caption 51 of 69 Photos: President Trump's first foreign trip Saudi King Salman shakes hands with Trump on May 21. Trump is the first US president to start his first foreign trip in the Middle East. Hide Caption 52 of 69 Photos: President Trump's first foreign trip Trump meets with other heads of state in Riyadh on May 21. Hide Caption 53 of 69 Photos: President Trump's first foreign trip Trump speaks with the Crown Prince of Abu Dhabi, Gen. Sheikh Mohammed Bin Zayed Al Nahyan. Hide Caption 54 of 69 Photos: President Trump's first foreign trip First lady Melania Trump chats with children during a visit to the American International School in Riyadh on May 21. Hide Caption 55 of 69 Photos: President Trump's first foreign trip While in Riyadh, President Trump meets with Bahrain's King Hamad bin Isa Al Khalifa on May 21. Hide Caption 56 of 69 Photos: President Trump's first foreign trip President Trump and Egyptian President Abdel Fattah el-Sisi share a laugh during a meeting on May 21. El-Sisi complimented Trump on his "unique personality that is capable of doing the impossible." Trump exchanged pleasantries back, praising el-Sisi's shoes. Hide Caption 57 of 69 Photos: President Trump's first foreign trip Trump is handed a sword during a welcoming ceremony at Riyadh's Murabba Palace on Saturday, May 20. Hide Caption 58 of 69 Photos: President Trump's first foreign trip Trump sits with members of his staff and Cabinet before a meeting with Saudi King Salman on May 20. Hide Caption 59 of 69 Photos: President Trump's first foreign trip Trump and King Salman take part in a signing ceremony at the Saudi Royal Court in Riyadh on May 20. The two leaders oversaw the signing of a defense deal worth nearly $110 billion. Hide Caption 60 of 69 Photos: President Trump's first foreign trip The Trumps look at a display of modern art at the Saudi Royal Court in Riyadh. Hide Caption 61 of 69 Photos: President Trump's first foreign trip King Salman presents Trump with a gilded necklace and medal, the country's highest honor. The distinction also was bestowed upon Presidents Barack Obama and George W. Bush. Hide Caption 62 of 69 Photos: President Trump's first foreign trip The first lady chats with Saudi Crown Prince Muhammad bin Nayef at the medal ceremony on May 20. Hide Caption 63 of 69 Photos: President Trump's first foreign trip Ivanka Trump attends the medal ceremony. Hide Caption 64 of 69 Photos: President Trump's first foreign trip Trump meets with King Salman after arriving in Riyadh on May 20. Hide Caption 65 of 69 Photos: President Trump's first foreign trip Soldiers on horseback carry the US and Saudi flags as they escort Trump to the Saudi Royal Court in Riyadh. Hide Caption 66 of 69 Photos: President Trump's first foreign trip Trump is welcomed by King Salman after arriving at the King Khalid International Airport in Riyadh. Hide Caption 67 of 69 Photos: President Trump's first foreign trip The Trumps take part in the welcome ceremony. Hide Caption 68 of 69 Photos: President Trump's first foreign trip The President and first lady wave from Air Force One after landing in Riyadh. Hide Caption 69 of 69

The NATO meeting in Brussels this week is markedly shorter than past summits, a scheduling decision made with Trump in mind. Substantive talks will last only a few hours over dinner, with the remainder of Trump's time at the meeting spent unveiling a new headquarters building. One US official suggested the agenda was designed to appeal to Trump's sensibilities as a developer and builder.

"The President prefers to keep folks on their toes and uncertainty could play into US strength," said Julianne Smith, a former deputy national security adviser to Vice President Joe Biden and now a senior fellow at the Center for a New American Security in Washington. "But for European allies across the continent, and that's from the north and the south, east, west, it's creating a tremendous amount of uncertainty and insecurity among our allies. They are looking to these meetings for clarity on US policy."

The injection of terror into Trump's first foreign trip is an echo of several episodes during President Barack Obama's international travels, when attacks regularly intruded into the message he was hoping to bring abroad.

Obama was just departing for a round-the-world swing through Turkey and Asia when the 2015 terror spree in Paris unfolded. He visited the French capital weeks later for a climate summit and laid a white rose at the Bataclan theater, where one of the massacres occurred.

A few months later, a bomb attack at the Brussels airport interrupted Obama's historic visit to Cuba. A later visit to Argentina was largely overshadowed by the aftermath. And stops last July in Spain were curtailed after a shooting death of five police officers in Dallas.