The evacuations expected Sunday of fighters and civilians from east Aleppo and two Shiite villages under rebel siege in northwestern Syria has been postponed until further notice, a monitor said.

The Syrian Observatory for Human Rights said the move was decided after gunmen attacked buses sent to evacuate people from the villages of Fuaa and Kafraya and in the "absence of security guarantees for the evacuees".

Yasser al-Youssef of the Nureddin al-Zinki rebel group confirmed that "the evacuations have been momentarily suspended".