BEIRUT, Dec 20 (Reuters) - Air strikes believed to have been carried out by Russian warplanes killed scores of people in the center of the rebel-held city of Idlib in northwest Syria on Sunday, rescue workers and residents said.

They said at least six strikes had hit a busy market place in the heart of the city, several government buildings and residential areas. Rescue workers said they had confirmed 43 dead but that at least 30 more bodies had been retrieved that had still to be identified. Over 150 people were wounded with some of the serious cases sent to hospitals in Turkey.

"There are a lot of corpses under the rubble," Yasser Hammo, a civil defense worker, said via an Internet messaging system, adding that volunteers and civil defense workers were still pulling bodies out.