Syrian warplanes struck several rebel-held areas across the country on Monday, killing over 40 people, activists said.

Air raids on the village of Jassem in the southern Daraa province killed at least 12 people and wounded 25, the Britain-based Syrian Observatory for Human Rights said. Daraa-based opposition activist Ahmad al-Masalmeh said 14 were killed in the air raids, including four children and two women.

The village has seen near-daily air strikes and fighting between government forces and rebels. Rebels have been on the offensive and captured a major military base late last month.

The Observatory, which relies on a network of activists on the ground, said other strikes hit villages in the northern province of Idlib, in the northern city of Aleppo, and in the town of Douma near Damascus. It said that in some raids government forces used crude bombs hurled out of helicopters. Other local organizations also reported the strikes, but gave different death tolls. Conflicting tolls are common in the chaotic aftermath of violent events.

Also on Monday, activists said a pro-government group known as the National Resistance Movement shot dead a man after accusing him of spying for Israel.

Al-Masalmeh said the dead man was a Syrian army defector from the central province of Hama who was recently wounded in a battle against government forces and later detained as he was returning to his hometown. He said the killing occurred on Saturday in Daraa province.

Syria's conflict has killed more than 220,000 people since the start of the uprising in March 2011, according to the United Nations.