BEIRUT (AP) — A building collapse in northwest Syria killed a woman and three of her children, while her husband and three other children survived, the opposition Syrian Civil Defense group said Thursday.

The collapse of the building Wednesday night on the southern edge of the city of Idlib came as northwest Syria has been witnessing weeks of rain and snow.

The Syrian Civil Defense, also known as the White Helmets, said rescue operations in the two-story building lasted about four hours. The mother and one of her children were already dead when rescuers pulled them out, while two children succumbed to their wounds shortly afterward, the civil defense said.

Later at night, the father and three other children were extracted alive and taken to the hospital for treatment.

Idlib province is the last rebel stronghold in war-torn Syria, and is home to about 3 million people, many of them internally displaced.

Syria’s conflict that began in March 2011 has killed nearly half a million people and displaced half the country’s pre-war population of 23 million.