The Syrian government launched a fierce air and ground assault on the last rebel-held town in eastern Ghouta on Friday, killing at least 32 people in a bid to seal President Bashar al-Assad’s biggest victory since 2016, a war monitor said.

State TV showed thick clouds of smoke rising from the targeted area, the town of Douma, where the Jaish al-Islam rebel group is holding out after insurgents in other parts of eastern Ghouta accepted safe passage to other rebel areas.

State TV said Republican Guard forces were pushing in.

Jaish al-Islam said its rocket and artillery brigade were responding to what it described as a massacre by “the Assad militias and their ally the Russian warplanes”. Jaish al-Islam’s political official called for talks to spare civilian bloodshed.

The Syrian Observatory for Human Rights, which monitors the war, said the 32 dead in Douma included five children and the air strikes were likely carried out by Russian war palnes. State media said rebel shelling of Damascus had killed four people.

Jaish al-Islam denied targeting residential areas.

A commander in the regional military alliance that backs Assad said Jaish al-Islam’s only option was to accept safe passage to rebel-held areas northeast of Aleppo as talks overseen by Russia had collapsed.

“The negotiations have ended with failure. As far as Douma is concerned, resolving it militarily is the solution,” the commander told Reuters.

Russian-backed government forces launched their offensive against eastern Ghouta in February. The Observatory says the attack has killed more than 1,600 civilians.

The conquest of Douma would underline Assad’s unassailable position in the conflict that mushroomed out of protests against his rule seven years ago.

Read more on Reuters.