AMMAN (Reuters) - Russian jets struck several rebel-held towns in northwest Syria's Idlib province for the first time since a ceasefire agreed with Turkey formally took effect two days ago, witnesses and insurgent sources said.
They said the towns of Khan al Subl, Maasaran and several others in southern Idlib were targeted after a two-day lull in aerial strikes on the last rebel bastion that had been pounded for over a month in a renewed assault.
"The Russian air strikes have shattered two days of relative calm that gave people a small relief from daily raids," said Mohamad Rashid, a civil affairs activist.
Later in the day, Syrian government and Russian air force jets hit two main markets, one in Idlib city where at least 15 people were killed, witnesses said. Footage by activists showed bodies strewn in debris-filled streets.
Rescuers said three other civilians were killed in attacks on several other towns since the aerial bombing resumed.
Moscow says its forces along with Syria's army and Iranian-backed militias are fending off attacks by al Qaeda militants whom they accuse of targeting populated, government-held areas in a "de-escalation zone" brokered in 2018 by Turkey and Russia.
Hundreds of thousands of people have fled Idlib province in recent weeks as Russian jets and Syrian artillery have pounded towns and villages in a renewed government assault aimed at clearing the opposition.
U.N. officials said this month the humanitarian crisis had worsened with at least 300,000 civilians now on the run in Idlib province on top of over half a million who fled earlier bouts of fighting to the safety of camps near the Turkish border.
The latest offensive has brought the Russian-steered military campaign closer to heavily populated parts of Idlib province, where nearly 3 million people are trapped, the vast majority women and children, according to the United Nations.
Moscow, Syrian President Bashar al-Assad biggest ally in his war with rebels and militants, announced earlier this week it had opened safe corridors to allow people under opposition rule in Idlib province to flee to government-held areas.
Residents say few people have crossed into state-controlled areas, where they fear retribution, while most have headed to the relative safety of areas near the Turkish border.
Many of the residents of the opposition enclave fear the return of Assad's authoritarian rule and look to Turkey to halt the Russian-led campaign that has killed hundreds and left dozens of towns and villages in ruins. Turkish President Tayyip Erdogan said his country was determined to stop Syrian government violations of the ceasefire in the northwest.
(Reporting by Suleiman Al-Khalidi and Khalil Ashawi; Editing by Mark Heinrich)