BEIRUT (Reuters) - Air strikes and government artillery killed at least 20 people, including 10 children, in the largely rebel-held Syrian province of Idlib on Tuesday, the Syrian Observatory for Human Rights said.

The Observatory, a Britain-based war monitor, said Russian or Syrian government warplanes pounded the rebel-held town of Khan Sheikhoun, killing seven children and two pregnant women.

Warplanes and government artillery also killed 11 people in the village of Baarbo in the southwest of the province, the monitor reported.

“The Russian Defence Ministry has denied information reported in multiple foreign media outlets about alleged strikes by the Russian Air Force in the region of Khan Sheikhoun near the city of Idlib,” Russia’s TASS news agency quoted a ministry spokesman as saying on Tuesday.

“Russian jets did not fly in the area on Nov. 8 and no missile strikes were carried out.”

Syria’s war pits President Bashar al-Assad, supported by Russian air power and Iranian-backed militias, against an array of mostly Sunni rebel groups, including some backed by Turkey, Gulf monarchies and the United States.

Idlib contains the largest populated area of Syria controlled by rebels - including nationalist groups under the banner of the Free Syrian Army and Islamist fighters including the former al Qaeda affiliate Jabhat Fateh al-Sham.