Syrian tanks and artillery pounded rebel-held neighbourhoods in the commercial hub of Aleppo on Sunday in a bid to retake control as President Bashar Assad's regime accused regional powerhouses Saudi Arabia, Qatar and Turkey of trying to destroy the country.

Activists say opposition fighters control large swathes of territory across Syria's largest city. The government has been struggling for a week to beat back their assault and stem the tide of recent rebel advances in the civil war.

The head of the main opposition group, the Syrian National Council, called for international help in arming the rebels to face the regime's heavy weaponry, particularly tanks.

Civilians fleeing

"If the international community cannot act, they should support the opposition with anti-tanks missiles and anti-aircraft rockets," Abdel Basset Sida told the Gulf News during a stopover in Abu Dhabi. "We seek international supporters to arm our uprising against the regime."

Saudi Arabia and Qatar have expressed willingness to help fund the rebels and they are believed to be funneling money through Turkey to the opposition, which is using it to purchase arms and equipment.

Syrian Foreign Minister Walid al-Moallem railed against interference by the region's Sunni powers in a rare public criticism of his Middle East neighbours. He accused them of supporting the rebels at the behest of Israel.

"Israel is the mastermind of all in this crisis," he said during a joint news conference in Tehran with his Iranian counterpart Ali Akbar Salehi . "They [Qatar, Saudi Arabia and Turkey] are fighting in the same front."

Syria's Sunni majority forms the backbone of the uprising while the regime is dominated by Assad's minority Alawite sect, an offshoot of Shiite Islam. Iran is Syria's only remaining ally in the Middle East, standing by Damascus throughout the 17-month uprising.

Amid fears of a massacre or a bloody final battle in Aleppo, civilians have been fleeing the city in ever greater numbers.

"Life in Aleppo has become unbearable. I'm in my car and I'm leaving right now," said a Syrian writer as he got ready to drive away. "There's shelling night and day, every day," he said over the telephone on condition of anonymity for fear of reprisals.

He painted a dire picture of daily life in the embattled city, torn between the government forces and those of the rebels.

"Bread, gasoline and gas are being sold on the black market at very high prices," he said. "Many things are in shortage."

Videos uploaded onto the Internet show deserted neighbourhood streets filled with rubble knocked off the multi-story apartment buildings by incoming mortar shells. Shards of broken glass also litter the streets and few windows appear to still be intact.

Since the rebel assault on Aleppo began a week ago, about 192 people have been killed, mostly civilians, according to the activist group Syrian Observatory for Human Rights. Some 19,000 people have died since the uprising began, the group says.

The regime strategy for now appears to be to soften the rebel positions with artillery before actually moving into the densely packed streets of the neighbourhoods where their tanks be at a disadvantage.

Activists reported heavy shelling of several areas of Aleppo as well as clashes in the southwestern neighbourhood of Salahhedine, which has been a rebel stronghold for the past week.

Rebels take town east of Aleppo

The rebels seem to be putting up a much more effective fight than before, occasionally succeeding in disabling or capturing the regime's heavy, Russian-made tanks.

A video posted online by activists Sunday showed rebels riding through the town of al-Bab in Aleppo province in a captured regime battle tank.

"Rebels have completely seized control of the town of al-Bab east of Aleppo. It is the biggest town in the Aleppo countryside," said local activist Mohammed Saeed. He added that another 200 fighters had entered the city Sunday to join the 1,000 fighters who had poured into the city over the past few days to repel the Syrian army's effort to regain control.

He also said rebels have received "a new batch of weapons and ammunition," but declined to say from where.

The battle for Aleppo, once a bastion of support for Assad's regime, is absolutely critical in the struggle for Syria's future. Rebels already control large sections of the neighbouring Idlib province, which borders Turkey, and if a major metropolis fell to them it could possibly create the nucleus of some kind of "liberated" territory that could receive further support from the international community — much the way eastern Libya became a rebel sanctuary during the fight against Moammar Gadhafi last year.

Yet Syria's rebels are still massively outgunned and it seems just a matter of time before Assad's massed forces outside the city of 3 million crush them, much the way a similar rebel assault on Damascus over a week ago was quashed.

"They mobilized all their armed terrorists and tried to capture Damascus in less than a week," Moallem said in Iran. "They were defeated. Today, they've gone to Aleppo and definitely they will be defeated in Aleppo."

Iran has provided Assad's government with military and political backing for years, and has kept up its strong support for the regime since the uprising began in March 2011. The rest of the Arab world, however, has turned against Syria and on Sunday, the Arab League once against condemned Damascus.

The group's secretary general, Nabil Elaraby, told reporters that the regime's Aleppo offensive "amounts to war crimes" and that those behind it will eventually be brought to justice. Speaking at the League's headquarters in the Egyptian capital of Cairo, he said the pan-Arab organization supported calls by Syrian opposition groups for an emergency meeting of the U.N. Security Council on the regime's assault on Aleppo.