Upcoming UN-backed Syria peace talks in Geneva have been pushed back until late February, Sergei Lavrov said on Friday.
The Russian foreign minister’s announcement came as he met representatives from some opposition groups in Moscow.
Lavrov did not explain the reasons for the latest delay.
The negotiations in Geneva were scheduled for February 8, after this week’s peace talks in the Kazakh capital Astana.
Meanwhile, on the ground in Syria, hardline opposition group Ahrar al-Sham said that six other rebel factions had joined its ranks on Thursday to form an alliance against the jihadists, formerly known as the al Nursra Front.
Nursra is said to have attacked Free Syrian Army units west of Aleppo this week. It accuses them of conspiring against it in the Astana talks.
The negotiations in Kazakhstan ended without a major breakthrough, though Russia, Iran and Turkey did agree to up-hold a fragile ceasefire in Syria.