Syria denied reports on Saturday that President Bashar al-Assad's deputy had defected and his forces pressed an offensive against rebels, bombarding parts of Aleppo in the north and hitting an insurgent-held town in the oil-producing east.

Vice-President Farouq al-Shara 'never thought for a moment about leaving the country', said a statement from his office broadcast on state television issued in response to reports that the veteran Baath Party loyalist had tried to defect to Jordan.

Assad, battling a 17-month-old rebellion led by Syria's Sunni Muslim majority that has turned into a civil war, has suffered a string of defections including his prime minister Riyadh Hijab two weeks ago.

Shara, whose cousin - an intelligence officer - announced his own defection on Thursday, is a Sunni Muslim from Deraa province where the revolt first erupted against Assad, from the minority Alawite sect which is an offshoot of Shi'ite Islam.

The 73-year-old former foreign minister kept a low profile as the rebellion escalated but appeared in public last month at a state funeral for three of Assad's top security officials killed in a bomb attack in Damascus.

The statement said he had worked since the start of the uprising to find a political solution to end the bloodshed and welcomed the appointment of veteran Algerian diplomat Lakhdar Brahimi as a new international mediator for Syria.

Brahimi, who hesitated for days to accept a job that France's UN envoy Gerard Araud called an 'impossible mission,' will replace former UN Secretary-General Kofi Annan, who is stepping down at the end of the month.

Annan's six-point plan to end the violence and move towards political negotiations was based on an April ceasefire agreement which never took hold. The conflict has deepened since then with both sides stepping up attacks.

Assad's forces have turned increasingly to air power to hold back lightly armed rebels in the capital Damascus and Aleppo, a northern commercial hub. More than 18,000 people have died and some 170,000 have fled the country as a result of the fighting, according to the United Nations.

The Syrian Observatory for Human Rights said the army bombarded neighbourhoods in Aleppo, Syria's largest city. Rebels hold several districts in the country's northern commercial hub and have tried to push back an army counter-offensive.

State television said soldiers 'cleared terrorists and mercenaries' - terms used by authorities to describe Assad's armed opponents - from the western district of Saif al-Dawla, where some of the heaviest fighting has taken place.

Internet footage which activists said was filmed in Saif al-Dawla on Saturday showed a plane making a low pass over buildings and dropping two bombs.

The Observatory also said at least 20 armoured vehicles moved into the eastern town of Mayadeen in Deir al-Zor province, where Syria's 200,000 barrels per day of oil are produced.

In the town of Tel, north of Damascus, local activists said the bodies of 40 people killed in bombardment were gathered together for a joint burial. A picture showed what appeared to be several corpses.-Reuters