Syria’s President Bashar al-Assad has told the Syrian army that the battle in the northern city of Aleppo will decide the outcome of the country’s escalating civil war.

In an address to troops on 1 August, Al-Assad said that the battle in Aleppo, the country’s biggest city, would decide the outcome of the conflict. “The fate of our people and our nation, past, present and future, depends on this battle,” said Al-Assad.

Syrian troops have launched heavy artillery and gunship attacks on rebel fighters in the city following the bombing of the regime’s National Security Bureau headquarters in Damascus on 18 July, which killed Defence Minister Daoud Rajha and Assef Shawkat, the brother-in-law of Al-Assad.

Despite heavy air and ground bombardment, Sausan Ghoshesh, spokeswoman for the UN mission in Syria, has told international media that rebel forces control large parts of the city and that they had acquired heavy weaponry, which includes tanks seized from captured government forces.

More than 135 people were reported to have been killed during heavy fighting in the city on 1 August. According to the UN, more than 200,000 people have fled Aleppo since the government assault began on the northern town.

Opposition factions are now beginning to prepare more seriously for what could happen Al-Assad’s regime is overthrown. Manaf Tlass, a former Syrian brigadier general from Al-Assad’s inner circle who defected from the ruling regime on 5 July, has reportedly put himself forward for a role in any transitional body.

There is considerable concern about the ability of a former regime figure like Tlass, or even the rebels, to unite the country after Al-Assad is removed. A report on Syria by the Brussels-based International Crisis Group says, “Increasingly intertwined with what is left of the power structure, much of the minority Alawite community feels that it has to kill to survive, or be killed trying”. It goes on to say that the opposition must also come up with a plan on how it would handle issues such as retaliatory violence, amnesty and ensuring the inclusion of all sectors of Syrian society.

Activists report that 20,000 people have been killed in Syria since the unrest began in March 2011.