The $110 billion deal for Saudi purchases of US defence equipment and services came at the start of an eight-day foreign tour that will take Trump also to Jerusalem, the Vatican and meetings with leaders in Europe.
Saudi Foreign Minister Adel al-Jubeir said deals worth in excess of $380bn had been signed on Saturday.
“That was a tremendous day. Tremendous investments in the United States,” Trump said at talks with Saudi King Salman.
“Hundreds of billions of dollars of investments into the United States and jobs, jobs, jobs.”
Air Force One had barely taken off when it was announced late on Friday that James Comey, the former FBI chief fired by Trump, had agreed to testify publicly about Russian interference in the US elections.
Warm welcome
The president and first lady Melania Trump were greeted by King Salman as they disembarked at King Khalid International Airport in Riyadh in the morning. Trump and his wife, who dressed conservatively in black but did not cover her hair as Saudi women are required to do, walked side-by-side to the tarmac where they both shook hands with the 81-year-old king.
It was a more favourable welcome than had been granted last year to Trump’s predecessor, Barack Obama, who was seen in the Arab kingdom as soft on Iran and hesitant on Syria.
The king was overheard lamenting the Syrian war to Trump. “Syria too used to be one of the most advanced countries. We used to get our professors from Syria.... Unfortunately, they too brought destruction to their own country. You can destroy a country in mere seconds, but it takes a lot of effort,” he said.
Trump’s response could not be heard.
Meanwhile, White House spokesman Sean Spicer hailed the defence agreement with Riyadh as the “largest single arms deal in US history”.
“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,” a White House official said.
Trump would give a speech on Islam to leaders of Muslim countries on Sunday.
For Riyadh the visit is an opportunity to rebuild ties with a key ally, strained under Trump’s predecessor Barack Obama who Arab Gulf states suspected of a tilt towards their regional rival Iran.
Speech to Muslim leaders
Sunday’s speech to dozens of Muslim leaders has been touted as a major event — along the lines of a landmark address to the Islamic world given by Obama in Cairo in 2009.
The speech will be particularly sensitive given tensions sparked by the Trump administration’s attempted travel ban targeting several Muslim-majority nations and accusations of anti-Islam rhetoric on the campaign trail.
While most US presidents make their first foreign trip to neighbouring Canada or Mexico, 70-year-old Trump has opted instead for the Middle East and Europe.
He travels to Israel and the Palestinian Territories on Monday and Tuesday, and then to the Vatican and to Brussels and Italy for Nato and G7 meetings.
Ignoring President Donald Trump’s past admonition, US first lady Melania Trump did not cover her head on Saturday when they arrived in Saudi Arabia on the opening leg of his first international tour since taking office.
Two years ago, then-citizen Trump criticised then-first lady Michelle Obama’s decision to go bare-headed on a January 2015 visit with her husband.
“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,” Trump tweeted at the time, including a short-hand spelling for “enough”.
Under the kingdom’s strict dress code for women, Saudi women and most female visitors are required to wear a loose, black robe known as an abaya, in public.
Most women in Saudi Arabia also cover their hair and face with a veil known as the niqab.
But head coverings aren’t required for foreigners and most Western women go without.
While Mrs Trump dressed conservatively on Saturday in a long-sleeved, black pantsuit accented with a wide, gold-coloured belt, her below-the-shoulder brown hair blew in the breeze at King Khalid International Airport in the capital city of Riyadh.
She followed the example set by other, high-profile Western women, including Mrs Obama.
On visits earlier this year, British Prime Minister Theresa May and German Chancellor Angela Merkel also shunned head coverings.
Then-first lady Laura Bush generally went without covering her head, though she once briefly donned a headscarf that she received as a gift.
Hillary Clinton, on trips to Saudi Arabia as Obama’s secretary of state, also did not cover her head.
Trump’s daughter, Ivanka, a senior White House adviser who is also accompanying her father, also left her head uncovered.
Saudi Arabia adheres to an ultraconservative interpretation of Islamic Sharia law where unrelated men and women are segregated in most public places. Women are banned from driving, although rights advocates have campaigned to lift that ban.
Guardianship laws also require a male relative’s consent before a woman can obtain a passport, travel or marry. Often that relative is a father or husband, but in the absence of both can be the woman’s own son.
