Turkey and Syria fired artillery and mortars across their volatile border for a fifth consecutive day on Sunday, in one of the most serious and prolonged flare-ups of violence along the frontier.
The exchange of fire stoked fears that Syria's civil war will escalate into a regional conflagration drawing in NATO member Turkey, once an ally of President Bashar Assad but now a key supporter of the rebels fighting to topple him.
Turkish Foreign Minister Ahmet Davutoglu had warned on Saturday that Ankara would respond forcefully to each errant Syrian shell that lands on Turkish soil.
Ankara's warning was coupled by an apparent diplomatic push by the Turkish leadership to promote Syrian Vice-President Farouk al-Sharaa as a possible figure to head a transitional administration to end the conflict in the country.
In an interview with Turkish state television TRT Saturday, Davutoglu said that al-Sharaa was a figure "whose hands are not contaminated in blood" and therefore acceptable to Syrian opposition groups.
It was not clear whether the Turkish stance was co-ordinated with other allies, but the candid remarks by Davutoglu suggested some consensus might be emerging over a future role for him.
Damascus denies it is facing a popular uprising, instead blaming the violence on a foreign conspiracy to punish it for its support for anti-Israeli groups such as Lebanon's Hezbollah.
Despite the government's claims of being on the brink of restoring stability, the violence across the country shows no signs of abating. Activists say that more than 30,000 people have been killed since the anti-Assad uprising began.
Karam reported from Beirut. AP writers Albert Aji in Damascus, Suzan Fraser in Ankara and Jamal Halaby in Amman contributed to this report.