U.S. President Donald Trump, in the first stop of his maiden trip abroad, received a regal welcome Saturday in Saudi Arabia, feted by the wealthy kingdom as he aims to forge strong alliances to combat terrorism while pushing past the multiple controversies threatening to engulf his young administration.

For one day, anyway, Trump appeared successful in keeping his domestic woes an ocean away, as he basked in the pageantry that began with an elaborate airport welcome ceremony punctuated by a military flyover and a handshake from Saudi King Salman.

Trump arrived in Riyadh besieged by the fallout from his firing of FBI Director James Comey and more revelations about the federal investigations into his election campaign's possible ties to Russia.

Trump and King Salman signed a series of agreements cementing their countries' military and economic partnerships. One is a military sales deal of about $110 billion US, taking effect effective immediately. Another $350-billion US arms deal is to play out over the next 10 years.

Trump smiles and dances with a sword in a traditional male-only sword dance at a welcome ceremony Saturday. (Jonathan Ernst/Reuters)

"That was a tremendous day. Tremendous investments in the United States," Trump said after a late day meeting with the Saudi crown prince.

Trump dances

The president briefly joined King Salman in a traditional male-only sword dance before a state dinner in his honour.

Swaying side to side, the president stood shoulder to shoulder with Saudis for the traditional dance, which includes drumming and singing.

U.S. President Donald Trump takes in the sights and sounds of Riyadh at a welcome ceremony for his visit to the country. 0:36

The dance took place outside the King Abdulaziz Historical Centre where First Lady Melania Trump, son-in law Jared Kushner and daughter Ivanka will join Trump to dine with the Saudi king and other senior Saudi royals.

The menu is to include an array of dishes, including steak and ketchup alongside the lamb and hefty portions of rice.

Trump and first lady Melania Trump arrive at a welcome ceremony at Al Murabba Palace. (Jonathan Ernst/Reuters)

The two nations released a joint statement in which they vowed to "dedicate themselves to strengthening their strategic partnership for the 21st century and to charting a renewed path toward a peaceful Middle East…"

They also announced a defence co-operation agreement and private sector agreements that are intended to create tens of thousands of new jobs in the U.S. defence industry.

"This package of defence equipment and services support the long-term security of Saudi Arabia and the Gulf region in the face of Iranian threats, while also bolstering the kingdom's ability to contribute to counter-terrorism operations across the region, reducing the burden on the U.S. military to conduct those operations," the White House said in a statement.

Saudi Arabia's King Salman bin Abdulaziz Al Saud, centre, welcomes Trump and his wife Melania Trump as they arrive aboard Air Force One at King Khalid International Airport in Riyadh. (Jonathan Ernst/Reuters )

It praised the agreements as a way to expand opportunities for U.S. in the region and support "tens of thousands of new jobs in the U.S. defence industrial base."

To coincide with Trump's visit, Saudi Arabia announced it will open a digital centre to monitor the online activities of ISIS and other militant groups.

'Proud of this relationship'

"As you have heard us say often, we have to defeat ISIS on the battlefield, but we really have to defeat ISIS in cyberspace," U.S. Secretary of State Rex Tillerson said at a news briefing.

"This is their recruiting tool. This is how they message to lone wolves around the world," he said.

King Salman, right, and Trump, left, react to applause after signing a joint security agreement at the Royal Court in Riyadh. (Jonathan Ernst/Reuters)

"We are proud of this relationship that we are embarking upon with the kingdom and are appreciative of the leadership of his Royal Highness King Salman in putting these initiatives forward," Tillerson said.

Tillerson said the agreements will serve the national security interests of both the U.S. and Saudi Arabia as they aim to "deter regional threats from Iran."

"We are closely co-ordinating our efforts in terms of how to to counter Iran's extremism, its exported extremism in particular, its support for foreign fighters, its payment of foreign fighters, its support of militia that are operating not only in Yemen, but in Iraq and in Syria," he said.

​Stops in Israel, Vatican City, Belgium, Italy

Trump is the only American president to make Saudi Arabia, or any majority Muslim country, his first stop overseas as president — a scheduling choice designed in part to show respect to the region after more than a year of anti-Muslim campaign rhetoric.

The president's stop in Saudi Arabia kicks off an ambitious international debut. After two days of meetings in Riyadh, Trump will travel to Israel, have an audience with Pope Francis at the Vatican, and meet with allies at a NATO summit in Brussels and the Group of 7 wealthy nations in Sicily.

White House senior adviser Jared Kushner, right, walks with his wife Ivanka Trump, the president's daughter, at the Royal Court Palace in Riyadh. (Evan Vucci/Associated Press)

As he arrived, the president waved from the doorway of Air Force One and then descended the steps, joined by his wife, Melania. The 81-year-old King Salman, who used a cane for support, was brought to the steps of the plane on a golf cart. The two leaders exchanged pleasantries and Trump said it was "a great honour" to be there.

Several jets then flew overhead leaving a red, white and blue trail.

Trump also tweeted that it was "great" to be in Saudi Arabia.

Great to be in Riyadh, Saudi Arabia. Looking forward to the afternoon and evening ahead. <a href="https://twitter.com/hashtag/POTUSAbroad?src=hash">#POTUSAbroad</a> <a href="https://t.co/JJOra0KfyR">pic.twitter.com/JJOra0KfyR</a> —@realDonaldTrump

White House officials hope the trip gives Trump the opportunity to recalibrate after one of the most difficult stretches of his young presidency. The White House badly bungled the president's stunning firing of FBI Director James Comey, who was overseeing the federal investigation into possible ties between Trump's campaign and Russia. On Wednesday, the Justice Department relented to calls from Democrats to name a special counsel, tapping former FBI chief Robert Mueller to lead the probe.

Moments after Trump lifted off for Saudi Arabia, more reports stemming from the Russia investigation surfaced and threatened to overshadow the trip. The New York Times reported that Trump called Comey "a real nut job" while discussing the ongoing investigation with two Russian officials visiting the White House earlier this month. He also told them that firing Comey had "taken off" the "great pressure" he was feeling from the investigation, the Times reported.

Adviser 'person of interest' in Russia probe

Meanwhile, The Washington Post reported that an unidentified senior Trump adviser was being considered a "person of interest" in the law enforcement investigation. In addition, Comey agreed to testify at an open hearing of the Senate intelligence committee in the near future, the panel said.

Despite his domestic troubles, Trump warm reception in Saudi Arabia may reflect that the kingdom's ruling family grew deeply frustrated with former U.S. president Barack Obama's detente with Iran and his restrained approach to the conflict in Syria.

Pictures of Trump and Saudi Arabia's King Salman bin Abdulaziz Al Saud are projected on the front of the Ritz-Carlton, where Trump is staying. (Jonathan Ernst/Reuters)

Saudi Arabia's elaborate welcome included billboards featuring images of Trump and the king that dotted the highways of Riyadh, emblazoned with the motto "Together we prevail." Trump's luxury hotel was bathed in red, white and blue lights and, at times, an image of the president's face.

A giant billboard bearing portraits of Trump and King Salman is seen on a main road in Riyadh. (Fayez Nureldine/AFP/Getty Images)

Melania Trump wore a black pantsuit with a golden belt and did not cover her head for the arrival, consistent with custom for foreign dignitaries visiting Saudi Arabia. In 2015, her husband had, in a tweet, criticized former first lady Michelle Obama for not wearing a headscarf during a visit to the kingdom.

For a president who campaigned on an "America First" platform, the trip is a crucial moment for U.S. allies to size up his commitment to decades-long partnerships while trying to move behind his previous controversial statements.

Speech to leaders of Muslim countries Sunday

Saudi Arabia's King Salman bin Abdulaziz Al Saud meets with U.S. President Donald Trump during a reception ceremony in Riyadh. (Jonathan Ernst/Reuters)

On Sunday Trump will hold meetings with more than 50 Arab and Muslim leaders heading converging on Riyadh for a regional summit focused largely on combating ISIS and other extremist groups.

The centrepiece of Trump's visit will be his speech at the summit. White House aides view the address as a counter to Obama's 2009 speech to the Muslim world, which Trump criticized as too apologetic for U.S. actions in the region.

Trump will call for unity in the fight against radicalism in the Muslim world, casting the challenge as a "battle between good and evil" and urging Arab leaders to "drive out the terrorists from your places of worship," according to a draft of the speech obtained by The Associated Press. The draft notably refrains from mentioning democracy and human rights — topics Arab leaders often view as U.S. moralizing — in favour of the more limited goals of peace and stability.

It also abandons some of the harsh anti-Muslim rhetoric that defined Trump's presidential campaign and does not contain the words "radical Islamic terror," a phrase Trump repeatedly criticized Hillary Clinton for not using during last year's campaign.​