Damascus: A missile strike near Syria’s biggest city Aleppo killed 26 people and government warplanes pounded Qusayr, a watchdog said on Monday, as a regime offensive to retake the town entered its third week.

The missile attack on the village of Kfar Hamra came as forces loyal to President Bashar Al Assad mounted a separate assault on the rebel-held countryside surrounding the northern city.

Al Assad’s opponents also suffered a political blow when one of the main groups in the National Coalition withdrew from the opposition bloc, amid accusations its leaders were misusing funds and acting in their own interests.

The Syrian Observatory for Human Rights reported the surface-to-surface missile attack on Kfar Hamra at around midnight killed 26 people, among them six women and eight children.

“Regime forces... are trying to take the village, and then to break the rebel siege of Nubl and Zahra,” two villages north of Aleppo, it added.

The attack comes a few days into a Syrian army offensive aimed at advancing on Aazaz, a rebel stronghold 45km north of Aleppo, the pre-war commercial hub.

Regime forces mounted a fierce onslaught on Qusayr, the strategic town near the Lebanese border, and also slightly farther north in Dabaa, the site of a disused military airbase partly under insurgent control.

The Observatory - which relies on a network of activists, lawyers and medics for its reports - said there were numerous dead on both sides, without giving any details.

An estimated 94,000 people have been killed in Syria since a peaceful protest movement that began in March 2011 quickly became an armed revolt when the regime cracked down hard.

Warplanes bombarded Qusayr for the second consecutive day, the Observatory said.

Three missiles, also believed to be surface-to-surface, also hit areas of the flashpoint town causing serious damage, the Observatory reported, but it was not known whether there were casualties.

The watchdog also reported air strikes on the Al-Hajar al-Aswad district of southern Damascus itself, where pillars of thick dark smoke barrelled into the sky.

It said clashes between soldiers and rebels were ongoing in the Abasiyeen area outside the capital’s Jubar neighbourhood. It was unable to give a casualty figure.

The Syrian Revolution General Commission said it was withdrawing from the Coalition because it was “taking initiatives far removed from the true revolution and cannot represent the revolution in an authentic way”.

The opposition faction, a Syria-wide network of activists, said some Coalition leaders were “more interested in appearing in the media than helping the revolution”.

As fears mount of the conflict spilling over, six people were killed and 38 wounded in 24 hours in Lebanon’s second city Tripoli as pro- and anti-Al Assad Alawite and Sunni residents clashed, a security source said.

Israeli Defence Minister Moshe Yaalon, meanwhile, said Russia cannot deliver a shipment of advanced anti-aircraft missiles to Syria before 2014.

Al Assad had hinted last week that his government may already have received a shipment of S-300 missiles, but Yaalon rebutted this.

“We are following this matter with concern, but no deliveries have taken place. If they do take place, it will not be before next year,” he said in remarks reported by army radio.

Monday’s fighting in Syria came a day after the regime said it would allow the Red Cross into Qusayr only when the fighting there stopped.

At the United Nations, diplomats said Russia blocked a draft Security Council declaration expressing “grave concern” about the situation in Qusayr.

They said Moscow was demanding “wider political discussion” on the issue.

Russia is a key ally of the Al Assad’s regime, which is also backed by Shiite Iran.

On Saturday, UN chief Ban Ki-moon and international aid groups expressed concern about civilians trapped in Qusayr, and for between 1,000-1,500 injured residents still in the town of 25,000 people.

But on Sunday, Syrian Foreign Minister Walid Mua’alem expressed surprise “given that no one expressed this concern when terrorists took control of the city and the surrounding area”.

Germany, meanwhile, joined France in saying that said the proposed “Geneva 2” peace conference on ending the bloodshed in Syria could be delayed until next month.

The international community has pinned its hopes for resolving the conflict peacefully on the US-Russian initiative that had been mooted for June in Geneva.