A Syrian watchdog group says rebels battling troops loyal to President Bashar al-Assad have taken over large parts of the northern city of Raqa after days of fierce fighting.
If the rebels seize control of Raqa — a provincial capital on the Euphrates river about 80 kilometers south of Turkey — it will be the first time an entire city will fall into the hands of anti-Assad fighters.
The Britain-based Syrian Observatory of Human Rights said rebels are fighting alongside al-Nusra Front Islamic fighters in the battle for the Raqa. The group posted amateur footage of residents toppling a statue of Assad's father and predecessor, Hafez al-Assad.
In Saudi Arabia on Monday, U.S. Secretary of State John Kerry and Saudi Foreign Minister Prince Saud al Faisal cautioned Assad that they will boost support to rebels unless he steps down.
Assad has rejected previous calls to step down, maintaining his government is fighting "terrorists," a term he frequently uses to describe the rebels.
Also Monday, in neighboring Iraq, unidentified armed men killed at least 42 Syrian soldiers who were being taken to the Syrian border after fleeing into Iraq during recent clashes with rebels.
Iraqi officials say several Iraqi government employees also were killed in the ambush of the convoy carrying the Syrians. The attack took place in Iraq's western Anbar province. The identity of the attackers is not clear.
The rebels now hold parts of several major Syrian cities, including Aleppo in the north, suburbs of the capital Damascus, and the central city of Homs. The gains are a significant blow to Assad's regime, which for two years has been battling an uprising that has escalated into a full-blown civil war.
The United Nations estimates that 70,000 people have been killed in Syria's conflict since March 2011.
Some information for this report was provided by AP, AFP and Reuters.