Meanwhile, opposition leaders said at least 50 people were killed Thursday in violence, CNN reported.
State-run media said two blasts occurred in a parking lot outside of the Justice Ministry, injuring at least three people and damaging 20 vehicles, state TV said.
Elsewhere in Syria, the Local Coordination Committees of Syria said least 50 people were killed, including 22 in the Damascus suburbs and 11 in Deir Ezzor.
Turkey said Thursday it was positioning anti-aircraft batteries along its border with Syria following the downing of one of Turkey's warplanes by Syrian forces.
Turkey's state broadcaster, TRT, ran video of military trucks carrying anti-aircraft guns, a rocket launcher and troops heading to border areas near Hatay where thousands of Syrians have fled from the increasing violence in the popular uprising against President Bashar Assad, The New York Times reported.
Other military equipment and personnel were deployed along the border settlement of Suruc, joining units near Mursitpinar, as well as in the coastal town of Iskenderun, TRT said.
Prime Minister Recep Tayyip Erdogan Tuesday said Turkey changed its rules of engagement toward Syria, warning Assad "every military element that approaches the Turkish border from Syria in a manner that constitutes a security risk or danger would be considered as a threat and would be treated as a military target."
A Turkish warplane was shot down under dubious circumstances off the Syrian coast about a week ago. The Turkish government said the plane was over international waters while Syrian officials said it was approaching the Syrian coast.
Omran al-Zoubi, Syria's information minister, was quoted as telling a Turkish broadcaster Syrian anti-aircraft gunners could have mistaken the Turkish plane for an Israeli one because the two countries' aircraft "look like each other." Israel and Turkey use U.S.-designed warplanes.
Zoubi said Syria did not want a confrontation with Turkey, a NATO member that has alliance support in its dispute with Syria concerning the downed plane.
Meanwhile U.N.-Arab League special envoy Kofi Annan, whose all-but-ignored peace plan is in danger of failing, announced Wednesday he would convene an "action group" meeting of influential countries in Geneva, Switzerland, Saturday to try to revive the six-point plan. However, Iran, a strong regional ally of Assad, and Saudi Arabia, a prominent supporter of Assad's foes, were excluded, the Times said.