The new US ambassador to Syria was sworn in on Friday and is expected to take up his post by the end of January, the State Department said, dpa reported.
Robert Ford becomes the first US ambassador to Damascus since Washington recalled its envoy after the assassination of Lebanon's former prime minister Rafik Hariri in 2005.
US authorities believed Syrian intelligence was behind the killing of Hariri in Beirut.
President Barack Obama named Ford to the post in an appointment at the end of the year, when Congress had already gone into recess.
Senate Republicans had blocked the nomination of Ford earlier in 2010, arguing the United States should not upgrade relations with Syria because of the country's continuing support for Shiite Muslim militia Hezbollah in Lebanon.
Obama used a constitutional rule that allows him to appoint nominees during congressional recess without having to acquire the Senate's confirmation. He must be confirmed by the Senate to serve past 2012.
State Department spokesman PJ Crowley said Friday that it was in the best interests of the United States to have higher-level communications with Damascus.
"Putting an ambassador in Damascus should not be viewed as a reward to the Syrian government," he said. "It improves our ability to deliver firm messages to the Syrian government and to articulate clearly our concerns and priorities to Syria."