Battles are raging in Syria's most populous city, Aleppo, as rebels continued their offensive to take the city that began three days ago.

Mataz Suheil, of the Britain-based Syrian Observatory for Human Rights, told VOA Saturday clashes broke out in Aleppo's Arkub and Azzizia neighborhoods. At least three rebel fighters were killed in fighting in the central Old City district, which was suffered heavy shelling.

Rebels announced a new offensive against government troops in Aleppo on Thursday, but it appears that neither side has made significant gains.

The Syrian Observatory says violence across Syria killed at least 45 people Saturday, bringing the death toll to nearly 31,000 since the uprising began in March of last year.