President Donald Trump kicked off his Middle East tour with a visit to Saudi Arabia on Tuesday, vowing a continued partnership between Washington and Riyadh.

RIYADH, Saudi Arabia (AP) — U.S. President Donald Trump opened his four-day Middle East trip on Tuesday by paying a visit to Saudi Arabia’s de facto ruler, Crown Prince Mohammed bin Salman, for talks on U.S. efforts to dismantle Iran’s nuclear program, end the war in Gaza, hold down oil prices and more.

President Donald Trump signed a $600 billion agreement with Saudi Arabia on Tuesday that includes a major defense contract and substantial investments in artificial intelligence—as U.S. business executives made their own set of deals at a conference in the backdrop of Trump’s visit to Riyadh, the first stop on his four-day tour of the Middle East.

President Trump announced the change in US policy during his speech at a Saudi investment forum, kicking off the first major international trip of his second term.

Investors eye more trade deals, updates from President Trump’s trip to the Middle East and fresh consumer inflation data after U.S. stocks soared Monday as investors celebrated major progress on U.S.-China trade talks.

The Trump family’s business ties to the Middle East have more than tripled since the president’s first term in office, a CNN a tally of the deals has found – including a slew of new projects announced since he reclaimed the White House.

President Donald Trump is expected to spend the majority of his 17th week back in the office traveling overseas to the Middle East.