The UN Security Council will meet for an emergency session on Monday after Syrian rebels declared the ouster of President Bashar al-Assad and took control of Damascus on Sunday.
The meeting, requested by Russia, will take place behind closed doors, diplomatic sources told dpa.
Syrians faced a new political reality on Sunday after rebels took the capital Damascus, ending the two-decade regime of al-Assad, who reportedly fled the country for Moscow.
A rebel alliance led by Islamist Hayat Tahrir al-Sham (HTS) launched a surprise offensive in northwestern Syria in late November and then quickly captured territory from pro-Assad forces as they moved toward Damascus.