The London-based opposition group Syrian Observatory for Human Rights accused President Bashar al-Assad's regime on Sunday of killing at least 80 people in the neighborhood of Jdeidet al-Fadel, with other activists putting the death toll in the hundreds.

Jamal al-Golani, a member of the Revolution Leadership Council opposition group, told the Reuters news agency that the number of dead could be higher than 250, with many of the victims shot at close range. He said that the presence of Syrian army patrols made it difficult to document all of the deaths.

Syrian government troops have waged a five-day offensive to retake Jdeidet al-Fadel, where up to 270 rebels have taken up positions, according to Golani, who said he had counted 98 bodies in the streets and 86 victims who had been summarily executed in makeshift clinics.

Abu Ahmad al-Rabi, an activist in the adjacent district of Jdeidet Artouz, gave his own account of the events.

"We documented 85 summarily executed, including 28 shot in a makeshift hospital after Assad's forces entered Jdeidet al-Fadel," Artouz told Reuters. "We fear that the victims of the massacre are much higher."

'Terrifying' figures

UN aid chief Valerie Amos told the UN Security Council on Thursday that some 6.8 million Syrians were in need of assistance, out of a population 20.8 million. She added that 4.25 million people were internally displaced in Syria.

The UN refugee chief, Antonio Guterres, told the council that the number of refugees could surpass 3.5 million by year's end. He said that over 400,000 people had fled the country over the past seven weeks.

"These figures are terrifying," Guterres said. "This is not just frightening: It risks becoming simply unsustainable."

US Secretary of State John Kerry on Sunday promised to double nonlethal aid to the Syrian opposition, increasing total American aid to $250 million (191.4 million euros).

slk/hc (AFP, Reuters, dpa)