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

3:20 p.m.

The United Nations special envoy for Syria says discussions have begun on a constitutional process as part of his mediation efforts to end the six-year-old civil war.

The office of Staffan de Mistura said Thursday there would be an expert-level meeting with representatives of the Syrian government delegation "on issues and ideas on constitutional process."

Meanwhile, the Syrian opposition said in a statement it sought clarification on 13 points including the mandate of the body and its frame of reference.

The envoy's proposal said the aim was to avoid a legal "vacuum" during an eventual political transition period.

Opposition spokesman Salem Meslet says talks are focusing on "the constitutional ground for a political transition process based on the formation of a body with full executive powers."

1:30 p.m.

The Islamic State group has launched an offensive against government forces in central Syria near the highway that links the capital Damascus to the northern city of Aleppo.

Thursday's attack comes as government forces are on the offensive against the extremists in other parts of Syria.

Syria's state news agency SANA said troops and pro-government gunmen repelled the IS attack on villages in Hama province.

The Britain-based Syrian Observatory for Human Rights said IS captured several army positions in the area and killed nine troops. It said troops launched a counteroffensive under the cover of airstrikes.

State TV said two people were wounded in IS shelling on the nearby town of Salamiyeh.

The IS-linked Aamaq news agency confirmed an attack is ongoing in the area without giving details.