Opposition fighters say the Syrian military is preparing to attack the country's second city, Aleppo. The UN, meanwhile, has appealed to the government and the rebels to spare civilians in what could be a major battle.
Rebel forces fighting for control of Aleppo say that thousands more government troops are readying for an assault on the northern city. The picturesque city, not far from the Turkish border, is already reportedly the scene of fierce fighting.
UN human rights chief Navi Pillay on Friday called on both sides in the conflict to spare civilians as a "major confrontation" appeared imminent.
"Civilians and civilian objects - including homes and other property, businesses, schools and places of worship - must be protected at all times. All parties, including the government and opposition forces, must ensure that they distinguish between civilian and military targets," Pillay said in a statement.
"This is the concern, that we will see a massacre in Aleppo, and that's what the regime appears to be lining up for," State Department spokeswoman Victoria Nuland told reporters in Washington. "Our hearts are with the people of Aleppo. And again, this is another desperate attempt by a regime that is going down to try to maintain control, and we are greatly concerned about what they are capable of in Aleppo."
Nuland added, however, that the US was not considering bolstered support for the opposition fighters, saying the US would continue providing non-lethal assistance.
"We do not believe that pouring more fuel on this fire is going to save lives," Nuland said.
Roughly three million people live in Aleppo. Syrian opposition forces, spearheaded by the Free Syrian Army (FSA), launched an all-out attempt to overrun Aleppo on July 20 - subsequently saying that their efforts were partially successful. The strategy is believed to be an attempt to establish a stronghold close to the rebel military headquarters on the other side of the Turkish border.
An FSA colonel told the AFP news agency via Skype that the reinforcements had arrived and that "we expect a major offensive at any time," possibly as early as Friday. Media close to the Syrian government have also acknowledged the situation, with the Al-Watan newspaper running with the Thursday headline "Aleppo, the mother of all battles."
Aleppo is a world heritage site, and UNESCO has called on fighters from all sides to protect Syrian cultural heritage.
msh, ncy/mz (AFP, AP, dpa, Reuters)