US President Barack Obama has renewed sanctions on Syria amid continuing concerns about its role supporting militants in the region, State Department spokesman Robert Wood said on Friday.
"The president felt it was necessary to take these measures. These are not new sanctions," Wood told reporters.
"I think this shows you that we still have some very serious concerns about Syrian behavior and activity in the world," he added.
"We've said to you before our concerns about what Syria is doing in Iraq, its support for terrorist groups. We've encouraged the Syrians to play a positive role in the Middle East," he said.
"We're willing to engage them in a dialogue to try to address not only our concerns but concerns that they may have. "But there's... no secret. We have some very serious problems with the government of Syria. And we hope to be able to try to work out those differences, but a lot of it is going to be up to Syria," he added.
The move comes as the United States tries to engage diplomatically with Syria and a senior US official Jeffrey Feltman returned to Syria this week as part of those efforts.
In Damascus, Feltman said he held "constructive" talks on Thursday with Syrian Foreign Minister Walid Muallem, on his second visit in two months to try to improve ties with Damascus.