President Trump said on Tuesday that he would lift sanctions on Syria, throwing an economic lifeline to a country devastated by nearly 14 years of civil war and decades of dictatorship under the Assad family.

Mr. Trump was expected to meet for the first time with Syria’s new president, Ahmed al-Shara, on Wednesday in Saudi Arabia, where he is making the first major state visit of his second term. Mr. al-Shara led the rebel alliance that ousted President Bashar al-Assad in December.

The U.S. president announced the end of sanctions on Syria as he addressed a business forum in the Saudi capital, Riyadh, where the crowd erupted in cheers and gave him a standing ovation.

The decision marks a sea change for Syria, breaking the economic stranglehold on a country seen as critical to the stability of the Middle East.

“There is a new government that will hopefully succeed in stabilizing the country and keeping peace,” Mr. Trump said. “That’s what we want to see in Syria.”

He said he came to the decision after speaking with Turkey’s president, Recep Tayyip Erdogan, who backed the anti-Assad insurgency, and Saudi Arabia’s crown prince, Mohammed bin Salman. The prince said this week he would work to increase Riyadh’s total pledged investment in the United States during the Trump presidency from $600 billion to the $1 trillion, as Mr. Trump has requested.