Russia and Turkey have signed an agreement spelling out mechanisms to "coordinate" their air forces in Syria when conducting strikes "on terrorist targets", the Russian defence ministry said Thursday.

Delegations from the two countries, which last month brokered a ceasefire in war-torn Syria, met in Moscow Thursday for consultations on cooperating while fighting Islamic State jihadists, signing a memorandum, the ministry said.

"The document defines the mechanisms to coordinate and cooperate by the Russian airforce and the Turkish airforce while carrying out strikes on terrorist targets as well as the actions by the sides to prevent incidents while planes and unmanned aerial vehicles are in Syrian airspace," it said.

Moscow and Ankara agreed to back a ceasefire last month between the Syrian government and rebel groups which went into effect on December 30 and has been observed in vast parts of the country, though clashes have continued to rock areas near Damascus.

The fighting has notably damaged water infrastructure risking further military escalation, United Nation's Syria envoy Staffan de Mistura said earlier Thursday, adding that meetings in Moscow and Ankara would be addressing the issue.