The Arab League's secretary general has offered the Syrian president, Bashar al-Assad, a "safe exit" for him and his family if he steps down.

Nabil Elaraby gave no further details on his proposal at an Arab League foreign ministers' meeting in Doha, Qatar, early on Monday morning.

The League also promised $100m (£64m) for Syrian refugees in neighbouring countries.

The Tunisian president, Moncef Marzouki, offered Assad asylum in February if it would end the conflict but the Syrian leader has shown little inclination to step down. On Sunday, his forces attacked remaining rebel pockets of resistance in the capital, Damascus.

In his first public statements since a devastating rebel bombing wiped out his top security officers, Assad told his new army chief of staff on Sunday to "continue the armed forces' pursuit of terrorists".

On the ground, fierce fighting continued on Monday in the cities of Damascus and Aleppo.

Government troops retook control of the Damascus neighbourhood of Mezzeh on Sunday and executed at least 20 unarmed men who they suspected of aiding rebels, opposition activists in the district said.

In the Barzeh district, members of the Syrian army's Fourth Division under the command of Assad's brother executed several young men during an operation to regain control of the northern Damascus district, a witness and activists said.

Government forces have launched a determined counter-offensive since rebels brought their battle to overthrow Assad to the capital and killed four of the president's closest associates in a bomb attack last Wednesday.