BEIRUT -- Syrian army helicopters fired on neighborhoods in Aleppo on Friday morning, activists said, killing at least a dozen people amid growing international alarm about the likelihood of a bloody siege by the government.
Residents reported dwindling fuel and bread and a tightening ring of military control. A senior rebel commander said he saw about 80 Syrian tanks on the city's southern outskirts Friday.
"They are preparing to reoccupy neighborhoods taken over by the rebels," said the commander, Lt. Malek al-Kurdi, by telephone in Syria. "They need a huge force."
The top U.N. human-rights official, Navi Pillay, warned of an "imminent confrontation" in Aleppo and said she had received unconfirmed reports of atrocities as the fighting escalated. She called on Syria's government and its opponents to protect civilians.
Saying a "a discernible pattern has emerged," Ms. Pillay accused the army of surrounding villages and cities, bombarding them, and then clearing the areas, often summarily executing suspected fighters. She also cited unconfirmed reports of opposition fighters torturing or executing prisoners.
Her comments came as the International Committee for the Red Cross said it would withdraw some expatriate workers from Damascus over fears the 17-month-old uprising is getting more perilous.
Meanwhile, two Western photojournalists in Syria held captive for a week by Islamic militants were rescued by Syrian rebels, one of the men said. Dutch photographer Jeroen Oerlemans told Business News Radio of The Netherlands he is not sure which group held him and John Cantlie of Britain, but said he is sure they were not Syrian.