The visit to Syria, a key ally of Iran, came amid soaring tensions in the Middle East between Iran and the United States. On Friday, a U.S. drone strike killed a top Iranian general who led forces supporting Assad in Syria's civil war. Iran has vowed revenge for the slaying, and with some 600 American troops deployed in Syria, the country is a potential site of conflict with Iran. While the official statements made no mention of the U.S. killing of Iran's Revolutionary Guard Gen. Qassem Soleimani on Friday, the timing was conspicuous. Soleimani had led Iran's armed support for Assad as armed rebels neared the capital, Damascus, and he helped seize key cities, preventing the collapse of Assad's state.