Hamas moved its headquarters to Syria in the late 1990s. But relations have soured since the regime violently suppressed an uprising that began as mostly peaceful protests. Many top Hamas leaders were based in Damascus until earlier this year when they moved to Qatar, Egypt and the Hamas-ruled Gaza Strip.
Activists and state media reported clashes, shelling and air raids in different parts of Syria.
The Britain-based Syrian Observatory for Human Rights said air raids on Houla, a group of villages in central province of Homs, killed seven people. The group also reported air raids on the Damascus suburbs of Douma and Maadamiyeh saying there are casualties without giving numbers.
SANA said six regime supporters were killed when 11 mortars rounds fell near a pro-government demonstration Monday night in the northern city of Aleppo.
Activists say more than 36,000 people have been killed in 19 months of fighting in Syria.
The Observatory said Syrian troops shelled two villages on the edge of the Israeli-occupied Golan Heights adding that government forces have been trying to take over the area for days.
On Monday, the Israeli military said a bullet from Syria struck one of its vehicles traveling on the Israeli side of the cease-fire line in the Golan Heights. No one was wounded in the incident. The Israel-Syria border has been quiet since a 1974 armistice agreement. Such incidents have been rare.
Israel is concerned that violence from Syria's civil war could spill into the country. Earlier this week, three Syrian tanks entered a demilitarized zone between the countries. Several Syrian shells, apparently misfired, have exploded inside Israel.
Rami Abdul-Rahman, who heads the Observatory, said an oil pipeline that carries crude from Al-Amr oil field in the eastern province of Deir el-Zour to a refinery in the central city of Homs blew up during fighting and shelling in the Homs suburb of Sultaniyah. Abdul-Rahman said it was not clear if the pipeline was targeted by a bomb or was hit by a random shell adding that the explosion causes a huge fire.
Oil pipelines have been subjected to sabotage attacks over the past months.
Associated Press writer Dale Gavlak in Amman, Jordan, and Suzan Fraser in Ankara, Turkey, contributed to this report.