At least 38 people were killed and scores wounded due to an attack on Monday on a crowded vegetable market of Idlib province in northwest Syria, according to rescuers and residents.  

The air raids, believed to be carried out by either Syrian or Russian jets, killed at least 50 people on Monday, with dozens injured. Thirty-six civilians and two unidentified individuals died in the market attack in Maarat al-Numan, a town of rebel-controlled province Idlib.  

Russia's Ministry of Defense on Monday denied its planes had carried out the latest airstrikes, saying they had not flown any missions in Idlib. 

Syria's government, backed by Russia, is trying to retake the northwestern province from rebels and jihadists. 

Idlib, along with Hama in the north and Aleppo in the west, remains one of the last three provinces held by the rebels after eight years of civil war.  

More than 350 people were killed last week and 330,000 were forced to leave their hometowns as the fighting between the government and rebels escalated since April. 

Busy marketplaces and residential areas have been frequently targeted during the campaign waged by Syria and Russia in order to combat the opposition.  

Airstrikes killed another six people in the town of Saraqeb on Monday. 

Syrian state media reported that several people had been injured by shells fired by rebels near the insurgent enclave. 

Residents said escalating strikes on urban centers have triggered a new wave of displacement towards the relative safety of the border area with Turkey. 

The offensive has so far failed to make major inroads into rebel territory in Hama and Idlib provinces, where mainstream rebels backed by Turkey alongside jihadist fighters are putting up fierce resistance in their last remaining bastion. 

Turkey, which reached an accord last September with Russia to contain the fighting and is seen by many civilians in opposition areas as a protector, said Moscow should pressure its Syrian ally to halt the bombing. 

"The responsibility to stop the regime attacks (in Idlib) is on our neighbor Russia," Turkish Foreign Minister Mevlut Cavusoglu told Turkish broadcaster TGRT Haber. 

U.S.-based Human Rights Watch said last month the Russian-Syrian operation had used "internationally prohibited and other indiscriminate weapons in unlawful attacks on civilians." 

Russia and the Syrian army deny allegations of indiscriminate bombing of civilian areas and say they are fighting al-Qaeda inspired Islamist militants.

(With input from agencies)