Syrian government forces have carried out a "poisonous gas" attack near the capital Damascus, leaving dozens of people dead, opposition groups said.
Activists said regime forces fired "rockets with poisonous gas heads" in the attack.
The Britain-based Syrian Observatory for Human Rights said the shelling was intense and hit the eastern suburbs of Zamalka, Arbeen and Ein Tarma. It said "tens of people" were killed.
The Local Co-ordination Committees said hundreds were killed or injured in the shelling.
There was no government comment on the claims.