RIYADH, Saudi Arabia -- President 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.

On day one, Mr. 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.

He later was given a tour of one of Riyadh's most opulent palaces and sat through an elaborate signing ceremony in which, one by one, the Saudis agreed to military deals with the U.S. government and private businesses.

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"That was a tremendous day. Tremendous investments in the United States," Mr. Trump said after a late day meeting with the Saudi crown prince, his only utterances to the press by late in the day. "Hundreds of billions of dollars of investments into the United States and jobs, jobs, jobs."

Saudi Arabia's King Salman bin Abdulaziz Al Saud meets with U.S. President Donald Trump during a reception ceremony in Riyadh, Saudi Arabia, May 20, 2017. REUTERS

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

The visit kicked off an ambitious international debut for Mr. Trump. After two days of meetings here, Mr. 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 powerful nations in Sicily.

Mr. Trump waved from the doorway after Air Force One touched down and before descending the staircase with first lady Melania Trump. The 81-year-old King Salman, who used a cane for support, was brought to the steps of the plane in a golf cart. The leaders exchanged pleasantries and Mr. Trump said it was "a great honor" to be there.

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

At a later ceremony at the grand Saudi Royal Court, the king placed the Collar of Abdulaziz Al Saud, the nation's highest civilian honor, around Mr. Trump's neck. The medal, given to Mr. Trump for his efforts to strengthen ties in the region, has also been bestowed on Russian President Vladimir Putin, British Prime Minister Theresa May and Mr. Trump's predecessor, Barack Obama.

The king and Mr. Trump were overheard discussing natural resources and arms, and the king bemoaned the destruction caused by Syria's civil war. Mr. Trump also agreed to a defense cooperation deal with the Saudis, pledging $110 billion effective immediately and up to $350 billion over 10 years, as well as some private sector agreements. The military package includes tanks, combat ships, missile defense systems, radar and communications, and cybersecurity technology.

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.

"President Trump understands that America First does not mean America alone," said H.R. McMaster, Mr. Trump's national security adviser. "Prioritizing American interests means strengthening alliances and partnerships that help us extend our influence and improve the security of the American people."

White House officials hope the trip marks an opportunity for Mr. Trump 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 Mr. 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.

As Mr. Trump flew to Saudi Arabia, more reports stemming from the Russia investigation surfaced. The New York Times reported that Mr. 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.

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, Mr. Trump was expected to get a warm reception in Saudi Arabia. The kingdom's ruling family grew deeply frustrated with Obama's detente with Iran and his restrained approach to the conflict in Syria. The king did not greet Obama at the airport during his final visit to the nation last year.

U.S. Secretary of State Rex Tillerson, standing shoulder to shoulder with Saudi Foreign Minister Adel al-Jubeir, reaffirmed their nations' joint commitment to capping Iranian aggression. But Tillerson hinted that the Trump administration may not look to completely shut Iran out, saying he'd be willing to speak to his Iranian counterpart "at the right time." He said he had no current plans to do so.

"In terms of whether I'd ever pick the phone up, I've never shut off the phone to anyone that wants to talk or have a productive conversation," Tillerson said.

Saudi Arabia offered Mr. Trump an elaborate welcome ahead of his two-day stay. Billboards featuring images of Mr. Trump and the king dotted the highways of Riyadh, emblazoned with the motto "Together we prevail." Mr. 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 President Donald Trump and Saudi Arabia's King Salman, is seen on a main road in Riyadh, on May 19, 2017. Giuseppe Cacace / AFP/Getty Images

Mr. Trump and the king met briefly in the airport terminal for a coffee ceremony before the president headed to his hotel before the day's other meetings. White House Chief of Staff Reince Priebus told reporters on Air Force One that Mr. Trump spent the flight meeting with staff, working on his upcoming speech to the Muslim world and getting a little sleep.

Mrs. 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. Mr. Trump's daughter, Ivanka, also eschewed a headscarf. In 2015, Mr. Trump criticized former-lady Michelle Obama for not wearing a headscarf during a visit to the kingdom.

Many people are saying it was wonderful that Mrs. Obama refused to wear a scarf in Saudi Arabia, but they were insulted.We have enuf enemies — Donald J. Trump (@realDonaldTrump) January 29, 2015

Ivanka's presence dominated Arabic Twitter traffic, with the phrase "bint Trump" -- Arabic for "daughter of Trump" -- trending.

On Sunday, he'll hold meetings with more than 50 Arab and Muslim leaders heading converging on Riyadh for a regional summit focused largely on combating the Islamic State of Iraq and Syria (ISIS) and other extremist groups.

Mr. 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 also notably did not contain the words "radical Islamic terror," a phrase Mr. Trump repeatedly criticized Hillary Clinton for not using during last year's campaign.