Dozens of people have died in a strike by government forces near the Syrian capital of Damascus, the London-based Syrian Observatory for Human Rights reported Sunday.
The group said at least 80 people had died in the community of Jdeid al-Fadl after five days of a government offensive there. Other activists put the death toll at 250. There were reports of executions.
However, the group was not able to substantiate its claims. Thorough reporting out of Syria remains difficult because of ongoing fighting and government controls on media, DPA reported.
The development came as the Jordanian government called on the UN Security Council to address the Syrian refugee crisis driving some 2,000 people into Jordan per day.
The Jordanian government said it would petition the council to address the "serious repercussions" of a refugee exodus that has resulted in some 500,000 Syrians entering into Jordan since March 2011, the state-run Petra news agency reported.
Jordan plans to highlight the growing social, security and economic burdens posed by hosting the refugee community, set to cost the country around 1.5 billion dollars this year, according to the agency.
The move comes less than two days after violent clashes in the country's largest Syrian refugee camp left 10 policemen and dozens of Syrians injured, sparking angry protests in the border city of Mafraq.
The government is under increasing public pressure to close the borders to Syrian refugees, with residents of border towns holding near-weekly "anti-Syrian" protests.
Jordanian lawmakers last month floated a proposal to relocate the refugees to so-called "buffer zones" within Syrian territory.
Earlier this month, the Jordanian Health Ministry, which spends one-third of its budget on medical aid for refugees, called for some 350 million dollars in emergency funds to sustain the country's public health sector.
A surge in violence in Syria has increased the refugee influx to Jordan to some 100,000 persons per month - a pace UN officials warn requires the opening of a new refugee camp every 30 days.