DOHA, Qatar -- President Donald Trump on Thursday will visit a U.S. installation at the center of American involvement in the Middle East as he uses his four-day visit to Gulf states to reject the “interventionism” of America’s past in the region.

Trump plans to address troops at Qatar’s al-Udeid Air Base, which was a major staging ground during the U.S. wars in Iraq and Afghanistan and supported the recent U.S. air campaign against Yemen’s Iran-backed Houthis. The president has held up Gulf nations like Saudi Arabia and Qatar as models for economic development in a region plagued by conflict as he works to entice Iran to come to terms with his administration on a deal to curb its nuclear program.

Before addressing the troops, Trump will take part in a roundtable with business leaders. The group includes top executives from Boeing, GE Aerospace and Al Rabban Capital.

Later Thursday, he will travel to Abu Dhabi in the United Arab Emirates for the final leg of his Mideast tour. He will visit the Sheikh Zayed Grand Mosque and be honored with a state visit with UAE President Mohammed bin Zayed Al Nahyan at the Qasr Al Watan palace.

Trump has also used his trip to announce plans to recognize the government of Syrian President Ahmad al-Sharaa and to ease sanctions on the war-torn country. The U.S. has deployed more than 1,000 troops in Syria for years to suppress a return of the Islamic State group.

Trump heaped praise on al-Sharaa — who was tied to al-Qaida and joined insurgents battling U.S. forces in Iraq before entering the Syrian civil war — after the two met in Saudi Arabia on Wednesday. The president called al-Sharaa a “young, attractive guy. Tough guy. Strong past. Very strong past. Fighter.”

It was a stark contrast from earlier years, when Al-Sharaa was imprisoned by U.S. troops in Iraq. Until December, there was a $10 million U.S. bounty for his arrest.

Trump, speaking in Saudi Arabia on his first day in the region, told Gulf leaders, “It’s really incredible what you’ve done. In the end, the so-called nation builders wrecked far more nations than they built, and the ‘interventionalists’ were intervening in complex societies that they did not even understand themselves.”

The Qatari base houses some 8,000 U.S. troops, down from about 10,000 at the height of the Iraq and Afghanistan wars.

The gas-rich Gulf country has spent some $8 billion over two decades in developing the base, built on a flat stretch of desert about 20 miles (30 kilometers) southwest of Qatar’s capital, Doha. The base was once considered so sensitive that American military officers would say only that it was somewhere “in southwest Asia.”

Trump said he and the emir of Qatar, Sheikh Tamim bin Hamad Al Thani, would also see a demonstration of American air capability, as the U.S. leader looks to boost defense exports to the region.

“You’re buying a lot of that equipment actually,” Trump said Wednesday when he and Sheikh Tamim signed a series of bilateral and business agreements between the two countries. “And I think we’re going to see some of it in action tomorrow at the — we won’t call it an air fair, but its going to be sort of an air fair. We’re going to be showing a display that’s going to be incredible. They have the latest and the greatest of our planes and just about everything else.”

Among the agreements the two leaders signed on Wednesday was a document clearing the way for Qatar to purchase American-made MQ-9B drones — the export version of the Reaper.

Trump told al-Sharaa that he wanted the new government to take control of prisons in Syria holding Islamic State fighters and their family members, who are currently guarded by U.S.-backed Kurdish fighters. If it comes to pass, it would further reduce the need for U.S. troops in the country.

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Madhani reported from Dubai. Associated Press writer Gabe Levin in Doha contributed to this report.