Two civilians were killed in Russian airstrikes in Syria's northwestern Idlib province on Tuesday, according to an opposition aircraft observatory.

Russian warplanes struck the towns of Kafr Nabl and Kafar Roma and several villages in the province, leaving two civilians dead, the observatory said.

Regime warplanes, meanwhile, targeted Al-Rawda Woman and Child Hospital in Kafr Nabl, leaving the hospital unusable.

At least 100 civilians have been killed and 50,000 people displaced in attacks by regime forces, Russia and Iran-backed groups in Idlib since October, according to the Syria Intervention Coordinators.

Idlib, home to 1.5 million people, is the last opposition enclave in Syria.

Late last year, President Recep Tayyip Erdoğan and his Russian counterpart Vladimir Putin reached an agreement for a cease-fire in Idlib and the withdrawal of heavy arms and radicals from the surrounding region.

The meeting in Sochi was part of the Astana process, which was held in Turkey in January 2017 to bring all warring parties in the Syrian conflict to the table to facilitate U.N.-sponsored peace talks in Geneva. Ankara often warns the international community and regional countries that a new offensive could trigger a fresh refugee wave toward the West.