ALEPPO - The government of Bashar al-Assad declared victory on Sunday in a hard-fought battle for Syria's capital Damascus, and pounded rebels who control of parts of its largest city Aleppo. Assad's forces have struggled as never before to maintain their grip on the country over the past two weeks after a major rebel advance into the two largest cities and an explosion that killed four top security officials. Government forces have succeeded in reimposing control of the capital after a punishing battle, but rebels are still in control of sections of Aleppo, clashing with reinforced army troops for several days. "Today I tell you, Syria is stronger... In less than a week they were defeated (in Damascus) and the battle failed," Foreign Minister Walid Moualem said on a visit to Iran, Assad's main ally in a region where other neighbours have forsaken him. "So they moved on to Aleppo and I assure you, their plots will fail." Rebel fighters, patrolling opposition districts in flat-bed trucks flying green-white-and-black "independence" flags, said they were holding off Assad's forces in the south-western Aleppo district of Salaheddine, where clashes have gone on for days. Opposition activists also reported fighting in other rebel-held districts of Aleppo, in what could herald the start of a decisive phase in the battle for Syria's commercial hub, after the army sent tank columns and troop reinforcements last week. Helicopter gunships hovered over the city shortly after dawn and the thud of artillery boomed across neighbourhoods. Syrian state television said soldiers was repelling "terrorists" in Salaheddine and had captured several of their leaders. Some rebel-held areas visited by Reuters were empty of residents. Fighters were basing themselves in houses - some clearly abandoned in a hurry, with food still in the fridges. A burnt out tank lay in the street, while nearby another one had been captured intact, covered in tarpaulin and left in a car park, perhaps for the rebels themselves to use against any ground assault by Assad's forces. In a largely empty street, flanked by closed shops and run-down buildings, women clad in long black abaya cloaks walked with children next to walls daubed with rebel graffiti - "Freedom", "Free Syrian Army" and "Down with Bashar". Rubbish lay uncollected and in one street families were packing vans full of mattresses in apparent preparation to flee. International peace envoy Kofi Annan and other foreign leaders said the situation in Aleppo served to emphasise the need for a negotiated political solution to the 16-month-old conflict in Syria. A peace plan proposed by Annan depends on a ceasefire that has been ignored. The leader of Syria's main political opposition group, the Syrian National Council, called instead for its foreign allies to provide heavy weapons needed to fight Assad's "killing machine". "The rebels are fighting with primitive weapons...We want weapons that we can stop tanks and planes with. This is what we want," SNC chief Abdelbasset Seida said in Abu Dhabi. He also urged foreign allies to circumvent the divided U.N. Security Council and intervene directly to help topple Assad. "Our friends and allies will bear responsibility for what is happening in Aleppo if they do not move soon," he said, adding that talks would start on forming a transitional government. Assad's ruling structure draws strongly on his Alawite minority sect, an offshoot of Shi'ite Islam, and the opposition is drawn largely from the Sunni Muslim majority, enjoying the support of Sunni leaders who rule nearly all Arab states.