State-run media, meanwhile, said government forces killed scores of 'terrorists' outside Damascus. The government routinely uses the term to describe opposition fighters, though members of Jabhat al-Nusra -- which the United States calls a terrorist group -- have reportedly joined the rebels in fighting.

In neighboring Turkey, a U.S. ship carrying Patriot air defense systems landed Wednesday at Iskenderun Port, according to the semi-official Anadolu Agency.

The spokesman for the Turkish general staff, Major Cengiz Alabacak, said that the systems would be deployed in the southeastern province of Gaziantep and would be operational by the middle of February.

NATO foreign ministers decided in December to deploy the batteries after Syria launched Scud missiles near the Turkish border. In October, errant Syrian artillery shells hit the Turkish border town of Akcakale.

The first of six Patriot missile batteries intended to protect Turkey from Syrian threats is operational along the countries' shared border, NATO said Saturday.

Turkish Foreign Minister Ahmet Davutoglu said this month that the missile batteries will stay only as long as there is a threat.

The Syrian crisis started nearly two years ago, when President Bashar al-Assad's forces cracked down on civilians peacefully protesting government policies.

The violence led to an armed uprising and escalated into a civil war, with al-Assad trying to defend four decades of family rule against rebels demanding his ouster.

But with neither side showing any indication of backing down, it's unclear how many more thousands of civilians may die.