BEIRUT (Reuters) – Jihadists and other rebel groups made advances against the Syrian army north of Hama on Thursday, a war monitor said, part of their biggest offensive for months, underscoring the bleak prospects for peace talks which resume later in the day.

Since the Hama offensive began late on Tuesday, the rebels have captured about 40 positions from the army including at least 11 villages and towns, the Syrian Observatory for Human Rights, a Britain-based war monitor, said.

A Syrian military source acknowledged that insurgents had launched a widescale assault in rural parts of Hama by what the source called a large number of terrorists, but said the attack had been contained.

The assault coincides with clashes in the capital Damascus, where rebels and the army are fighting on the edge of the city center in the Jobar district for a fifth day amid heavy bombardment, state media and the war monitor reported.

It seems unlikely to reverse 18 months of steady military gains by the government, culminating in December’s capture of the rebel enclave in Aleppo, but it has shown the army’s difficulty in defending many fronts simultaneously.

Increased fighting, despite a ceasefire brokered in December by Russia and Turkey, casts further doubt on peacemaking efforts in Geneva, where talks resume on Thursday after making no progress towards peace in recent rounds.

“We hope to see some serious partner on the other side of the table,” Salem al-Muslet, spokesman for the opposition’s High Negotiating Committee (HNC), said in Geneva.

Syrian President Bashar al-Assad’s government, backed by Russia, Iran and Shi’ite militias, is attending the Geneva talks. Both sides accuse each other of violating the ceasefire.

Near Hama, rebels spearheaded by the jihadist Tahrir al-Sham alliance, but including groups fighting under the banner of the Free Syrian Army, made new advances overnight and fighting continued on Thursday, the Observatory said.

By Thursday lunchtime they had defeated army forces in about 40 towns, villages and checkpoints, north of Hama, having advanced to within a few kilometers of the city and its military airbase, it said. In one area, the rebels took the village of Shaizer, nearly encircling the army-held town of Moharada.

HAMA AND DAMASCUS

On Wednesday, the Syrian military source said reinforcements were headed to the Hama front.

Tahrir al-Sham’s strongest faction is the former Nusra Front group, al Qaeda’s official affiliate in Syria until they broke formal ties last year.

One of the villages involved in the fighting is inhabited mainly by Christians.

The United States, which has supported some FSA groups during the war along with Turkey and Gulf monarchies, has carried out air strikes targeting Tahrir al-Sham leaders since January.

Samer Alaiwi, an official from the Jaish al-Nasr FSA group, which is fighting near Hama, said on a rebel social media feed that the offensive was aimed at relieving pressure on rebels elsewhere and stopping warplanes from using a nearby airbase.

“After the failure of political conferences and solutions, the military operation is an urgent necessity,” he said.

In Damascus, the intensity of clashes around the industrial zone in Jobar increased after midnight, the Syrian Observatory for Human Rights reported.

A military media unit run by the government’s ally Hezbollah reported clashes on Thursday in Jobar and heavy bombardment aimed at rebel positions and movement in the area.

State TV showed a reporter speaking in the capital’s Abassiyin district at morning rush hour, but the road appeared quiet with only one or two cars and a few pedestrians, and with the repeated sound of blasts in the background.

(Reporting By Angus McDowall and Tom Perry; Additional reporting by Issam Abdallah in Geneva; Editing by Janet Lawrence)