WASHINGTON - The Obama administration has renewed sanctions against Syria due to serious concerns over its behavior, despite sending two top envoys to Damascus this week to try to improve ties, U.S. officials said on Friday.

We continue to have serious concerns about Syria's actions, said State Department spokesman Robert Wood.

While the United States has made clear it wants better ties with Syria, a nation it has long accused of supporting terrorism, the renewal of sanctions shows it is not yet ready for a dramatic improvement in relations.

We need to see concrete steps from the Syrian government to move in another direction, Wood told reporters.

Obama signed an executive order on Thursday renewing the sanctions, shortly after two U.S. envoys met Syrian Foreign Minister Walid al-Moualem in the Syrian capital.

The visit by senior State Department official Jeffrey Feltman and White House National Security Council official Daniel Shapiro was their second since Obama took office in January and started talking to Damascus.

This reversed a policy of isolation under his predecessor President George W. Bush, who first signed executive order 13338 in 2004 blocking the export of certain goods to Syria and the assets of some individuals.

The two U.S. officials told their Syrian counterparts that the United States was committed to pursuing a peace deal between Syria and Israel, a main foreign policy objective for Damascus.

But the meeting also discussed Syria's role in Iraq and Lebanon and its relationships with militant groups in the Middle East -- issues that have contributed to deteriorating ties between Damascus and Washington in recent years, according to sources familiar with the meeting.