All evidence points to Syrian President Bashar al-Assad being behind a suspected chemical weapons attack which left more than 70 dead in a rebel-held town, British Foreign Secretary Boris Johnson said Wednesday. 

The EU and U.N. on Wednesday rallied donor countries and aid groups to support a devastated Syria at a conference overshadowed by a suspected chemical attack blamed by the West on Damascus.

Russia defended its ally Damascus on Wednesday in the face of an international outcry over a suspected chemical attack that killed scores of civilians, saying a Syrian air strike hit a "terrorist warehouse."

Russia's military on Tuesday said its planes did not carry out any strikes near the town of Khan Sheikhun in Syria, where air strikes hit a hospital as doctors treated victims of a suspected chemical attack.

Turkish President Recep Tayyip Erdogan in a phone call with Russian counterpart Vladimir Putin Tuesday condemned a suspected chemical attack in northwestern Syria as an "inhuman" strike that could endanger peace talks based in the Kazakh capital.

Warplanes carried out a suspected toxic gas attack on a rebel-held town in northwestern Syria on Tuesday, killing at least 58 people, the Syrian Observatory for Human Rights monitor said.

For years, Abboud Jan's gun repair shop in the northeastern Syrian city of Hasakeh catered exclusively to local hunters, but the country's devastating six-year war has changed all that.

Syria's army and allied fighters have regained most of the territory they lost during an assault launched by rebels and jihadists earlier this month in the country's center, a monitor said Friday.

"The regime has recaptured 75 percent of the territory it lost in the north of Hama province," said Rami Abdel Rahman, director of the Britain-based Syrian Observatory for Human Rights monitor.

Syrian jihadists and allied rebels advanced against government forces in central Hama province on Thursday, the Syrian Observatory for Human Rights monitor said.

Rebels and jihadists on Tuesday launched a fresh assault on east Damascus, two days after Syrian government forces repelled an initial attack just a few kilometers from the center of the capital.

An AFP journalist in east Damascus and a monitor both reported a large explosion at dawn followed by fierce clashes, shelling and government air strikes on opposition positions.