The last US ambassador was withdrawn from Damascus in 2005
Washington has confirmed it is to send an ambassador to Damascus, ending a four-year diplomatic absence in Syria.
The apparent move is being seen as part of President Barack Obama's attempts to increase engagement with the region.
The US Middle East envoy, George Mitchell, recently visited Syria and said Damascus had an "integral role" in finding peace in the region.
The US envoy in Syria was withdrawn in 2005, following after the assassination of Lebanon's former PM Rafiq Hariri.
There is widespread suspicion inside and outside Lebanon that Syria was involved in Mr Hariri's death, but Damascus strongly denies this.
A US official told the BBC that ''a decision in principle had been taken'' to send a US ambassador to Damascus, but added that the process would take time.
Any ambassador would have to be confirmed by the Senate, and no names have been discussed yet, the BBC's Kim Ghattas in Washington says.
Mitchell: "Syria has an integral role to play"
Washington said it had already informed Syria of its move.
State Department spokesman Ian Kelly said the decision reflected Syria's important role in the region, adding that Washington hoped it would be a constructive one.
Another state department official said the decision was in line with President Obama's decision to engage diplomatically to resolve a number of issues of concern to the US.
Peace with Israel, Syria's support for militant groups like Hezbollah and Hamas, as well the influx of foreign fighters from Syria into Iraq are all on the agenda, our correspondent says.
Four delegations of high-level US officials visited Damascus over the last few months, including a military delegation.
As the US starts its draw down of troops from Iraq, it is trying to ensure the situation there does not unravel, our correspondent adds.