BEIRUT (AP) — A war monitor and rescue workers are reporting government bombardment of rebel-held areas in Syria's northwest.

The Britain-based Syrian Observatory for Human Rights said Monday's airstrikes on Idlib and Hama provinces forced some people to flee their homes.

The opposition's Civil Defense, also known as the White Helmets, said 11 people were wounded in an attack on the village of Heesh.

Government forces, backed by Russia and Iran, have been massing troops for weeks in preparation for an attack on Idlib province that is the last major rebel stronghold in the country.

The U.N. has warned that a battle over Idlib and Hama will spark a humanitarian catastrophe. More than 3 million people live in the territory, nearly half of them already displaced from fighting elsewhere in Syria.