Al-Jazeera news channel said one of its freelance reporters in northern Syria was killed Monday in an air strike by Russian forces supporting President Bashar al-Assad's regime.

Ibrahim al-Omar, who reported for the Al-Jazeera Mubasher live channel, was killed "in Russian air strikes on the town of Termanin" in northern Idlib, the Doha-based channel said.

The Britain-based Syrian Observatory for Human rights said five people were killed Monday in air strikes on Idlib province, in northwestern Syria, including three slain in Termanin.

The other two were killed in strikes on the town of Ihsem, south of Idlib city.

Al-Jazeera has seen at least six members of its staff killed while covering the Syria conflict, which broke out in 2011.

The latest was in December when cameraman Zakaria Ibrahim was shot dead by a sniper in Homs province, the channel said.

Statistics provided by Paris-based Reporters Without Borders says seven journalists were killed in Syria last year, while 15 were killed in 2014.