Damascus: Elite Syrian and Hezbollah fighters rushed on Wednesday to Qusayr, bidding to finally overrun rebels in the strategic town in a battle that could turn the tide of an increasingly sectarian war, a watchdog said.

Despite having opposing positions, President Bashar Al Assad’s most powerful ally Russia and the United States, which has called for the president to resign, have been trying to organise a conference aimed at ending the conflict.

Hopes are building for the peace conference to be held in Geneva next month, but serious obstacles could still scupper the talks — not least divisions within the ranks of the Syrian opposition.

Hezbollah, the powerful Lebanese Shiite movement, whose fighters are spearheading the government assault has now reclaimed 80 per cent of the central town.

Government fighter jets early on Wednesday bombed rebel zones of the town as regime forces readied to launch a major new assault, said the Syrian Observatory for Human Rights watchdog.

The crack troops of the Republican Guards pouring into Qusayr have been trained in urban guerrilla warfare, like militiamen from Hezbollah, said Rami Abdul Rahman, director of the Britain-based Observatory.

“The preparations indicate that they are gearing for a major offensive” on rebel-held areas in the town’s north and west, he told AFP, adding that “despite the intense bombardment, the rebels are resisting fiercely.”

Sunni militiamen from Lebanon had joined the battle on the side of the rebels, and “the fighting is becoming more and more sectarian in character,” said Abdul Rahman.

Syria’s regime is dominated by the minority Alawite community, an offshoot of Shiite sect, while the majority of the population are Sunnis.

Control of Qusayr is essential for the rebels as it is their principal transit point for weapons and fighters from Lebanon.

The town, which is home to 25,000 people, is also strategic for the regime because it is on the road linking Damascus with the coast, its rear base.

“If Qusayr falls into the hands of the regime, it will be a hard blow for the rebels because routes used to bring in their arms from Lebanon will be closed,” said Abdul Rahman.

“If Qusayr was not strategic, the rebels would not be fighting to the death and the regime and Hezbollah would not have brought in their heavyweights,” said the head of an organisation that relies on a network of sources on the ground for its reports.

Iran-backed Hezbollah sent almost 1,700 fighters to Qusayr more than a week ago to support the regime’s assault on the rebel stronghold.

Hezbollah chief Hassan Nasrallah has promised his fighters will help deliver “victory” in the battle, seen as pivotal in Syria’s drawn out civil war in which more than 94,000 people have died.