The UN-backed ceasefire taskforce on Syria will meet on Friday at Russia's request, the United Nations' special envoy for Syria said, after the United States struck a regime airbase overnight.

"An emergency meeting of the ISSG (International Syria Support Group) Ceasefire Taskforce will take place later today," the office of special envoy Staffan de Mistura said. "The meeting, which will be chaired by the Special Envoy, was requested by the Russian Federation co-chair and agreed upon by the United States co-chair."