Following the completion of the withdrawal, Turkey’s military operation would be “halted entirely,” Pence said. The United States had already been in contact with the Syrian Kurdish militias, known as the Syrian Democratic Forces (SDF), and “we have already begun to facilitate their safe withdrawal,” Pence added.The Trump administration had also agreed not to impose any new economic sanctions on Turkey, and to withdraw sanctions that were imposed earlier this week once “a permanent cease-fire was in effect,” Pence said.The agreement, aimed at separating hardened foes, in a volatile area of Syria, in the midst of a civil war, faced obvious obstacles. But it averted, at least temporarily, the most serious dispute between Turkey and the United States in years. And, on paper at least, it provided Erdogan with much of what he was seeking, including the removal of Syrian Kurdish militias from the border as well as the threat of crippling sanctions, a specter that had hovered over Turkey’s vulnerable economy.President Trump had faced harsh criticism from stalwart Republican allies over the Turkish offensive, and for the perception that he had signaled his approval to Erdogan before the military operation began. “I didn’t know it was going to work out this quickly, I didn’t know it was going to work out this well,” he told reporters on Thursday in Texas, after Pence’s announcement.“It’s a great day for the United States, it’s a great day for Turkey,” he said. “A great day for the Kurds, it’s a great day for civilization, a great day for civilization,” he added.A representative for the SDF did not immediately respond to a request to comment on the agreement. Luqman Ahmi, a spokesman for the Kurdish administration in northeastern Syria, said the movement would release a statement soon. “We never asked for war, war was imposed on us,” he said.Pence’s whirlwind trip to Turkey came just a week after the start of a military operation that had hastened a withdrawal of U.S. troops and led to dire warnings about the resurgence of the Islamic State militant group as the fighting worsened.And the Trump administration was chastised for abandoning its own allies: the Syrian Kurdish militias who partnered with the U.S. military to fight the Islamic State.Before Thursday’s breakthrough, Erdogan had repeatedly rebuffed appeals for a cease-fire and chided Western allies for suggesting he negotiate with “terrorists,” as he refers to the Syrian Kurdish militias because of their links with the Kurdistan Workers’ Party, or PKK, which has fought an insurgency in Turkey for decades.Pence said Thursday that the Kurdish fighters would honor the deal struck between the United States and Turkey. “We have repeated assurances from them that they will be going out,” he said, referring to the SDF.Pence’s mission came a day after the White House made public a letter Trump had sent to Erdogan on Oct. 9 urging the Turkish leader to make a deal with the Syrian Kurds.“You don’t want to be responsible for slaughtering people,” Trump wrote, concluding: “Don’t be a tough guy. Don’t be a fool!” The letter was written on the day Turkey’s military operation started. Turkish officials told the BBC and other news outlets Thursday that Erdogan threw the letter in the trash.“But the most clear answer to the letter that was written on October 9 was the Peace Spring Operation,” CNN Turk reported, citing diplomatic sources and using Turkey’s code name for its offensive. On Wednesday, the U.S. military withdrew from Raqqa, the former de facto capital of the Islamic State, as well as Tabqa and a major headquarters at the Lafarge Cement Factory in Jalabiya, Col. Myles B. Caggins III, a U.S. military spokesman, said in a tweet.At the cement factory, after American troops had left, U.S. forces used F-15 jets to carry out airstrikes on parts of the headquarters to “destroy an ammunition cache and reduce the facility’s military usefulness,” Caggins wrote.In addition to the ammunition, the strikes targeted a small compound that was ringed with blast walls and included living quarters and diesel power generators, said a U.S. military official, speaking on the condition of anonymity because of the sensitivity of the operation.Dadouch reported from Beirut and Itkowitz from Washington. Erin Cunningham in Istanbul, Asser Khatab in Beirut and Dan Lamothe in Washington contributed reporting.