BEIRUT: The commander of Syrian rebels in the northern province of Aleppo says his forces have launched an operation aimed at ''liberating'' the country's largest city from regime troops.

Sunday's statement by Col. Abdul-Jabbar Mohammed Aqidi posted by activists on YouTube came as clashes in the country's commercial hub of Aleppo raged for a third day.

The Britain-based Syrian Observatory for Human Rights and Aleppo-based activist Mohammed Saeed said the fighting is concentrated in several neighborhoods.

The Observatory also reported attacks by government forces in the capital Damascus in the neighborhoods of Mazzeh and Barzeh.

Damascus and Aleppo are both home to elites who have benefited from close ties to Assad's regime, as well as merchant classes and minority groups who worry their status will suffer if Assad falls.