BEIRUT (AP) — The Latest on Syria developments (all times local):

3:10 p.m.

Britain and France are denouncing as a stunt and an "obscene masquerade" a move by Russia to produce Syrian witnesses who Russia says were filmed in "staged videos" in the aftermath of a reported chemical weapons attack.

Thursday's briefing at the Organization for the Prohibition of Chemical Weapons is seen as an effort by Russia to discredit widespread reports of an April 7 chemical weapon attack in the town of Douma that killed more than 40 people and was blamed by the West on President Bashar Assad's government. Syria and Russia deny the claims.

French Ambassador Philippe Lalliot says: "This obscene masquerade does not come as a surprise from the Syrian government, which has massacred and gassed its own people for the last seven years."

Britain's ambassador, Peter Wilson, says he and other Western allies will not attend the briefing.

11:50 a.m.

Syrian state media is reporting that government forces have pushed into a Damascus neighborhood held by the Islamic State group from different directions and captured buildings on several street blocks and tunnels used by the extremists.

State news agency SANA said Thursday that dozens of IS fighters were killed in battles in the southern Damascus neighborhood of Hajar al-Aswad during which ground forces closely coordinated with the air force in bombarding the area.

The opposition's Britain-based Syrian Observatory for Human Rights said Syrian authorities ordered rebel groups in the southern Damascus suburbs of Babila, Beit Sahm and Yalda to hand over fronts lines with IS in the area or face government bombardment.

The Observatory said the government wants to open new fronts against IS to expand pressure on the extremists.