The UN's top human rights official has urged the international community to take "immediate measures" to protect civilians in Syria as the death toll from the anti-government unrest rose above 3,000.
Navi Pillay, the UN High Commissioner for Human Rights, warned that the crackdown by the government of President Bashar Assad could worsen unless further action is taken.
"The onus is on all members of the international community to tale protective action in a collective and decisive manner, before the continual ruthless repression and killings drive the country into a full-blown civil war," Ms Pillay said in a statement.
She did not say what measures the international community could take beyond the sanctions already imposed on Mr Assad's regime.
Her spokesman, Rupert Colville, told reporters in Geneva that it was up to the UN Security Council to decide what action was appropriate.
But he added: "What has been done so far is not producing results and people continue to be killed every single day.
"Just hoping things will get better isn't good enough, clearly," he said.
The UN human rights office estimates that more than 3,000 people have now been killed since mid-March - about 10 to 15 people every day. The figure includes at least 187 children. More than 100 people had been killed in the last 10 days alone, the global body said.
Mr Colville said hundreds more protesters have been arrested, detained, tortured and disappeared. Families of anti-government protesters inside and outside the country have also been targeted for harassment.
Since mid-March, Mr Assad's regime has cracked down on protesters leading movements similar to those that have ousted other Arab dictators this year.