Russia's Defense Ministry denied on Monday its planes carried out airstrikes on the rebel-held Syrian city of Maarat al-Numan that hit a popular market and residential neighborhoods.

The raids killed at least 20 people in the densely populated city in the south of Idlib province earlier on Monday and were believed to have been carried out by either Syrian or Russian jets, rescuers and residents said.

"Russia's Air Force did not carry out any missions in the given region of the Syrian Arab Republic," the ministry said in a statement.