The international community must take "immediate measures" to protect civilians in Syria as the death toll from seven months of anti-government unrest in the country rose above 3,000, the UN's top human rights official says.

Navi Pillay, the UN High Commissioner for Human Rights, warned that the unrelenting 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 take protective action in a collective and decisive manner, before the continual ruthless repression and killings drive the country into a full-blown civil war," Pillay said in a statement.

Canadians urged to leave Syria

On Friday, the government urged Canadians in the beleagured country to leave immediately, and said Canadians should refrain from travelling there, citing security concerns.

"There has been extensive use of force by the security forces and military in suppressing demonstrations across [Syria]," a release from Foreign Affairs said. "Many casualties and fatalities have been reported and protests and violent repression are likely to continue."

Canadians in Syria should be cautious, avoid travelling at night and avoid political gatherings or crowds. 

She didn't elaborate on what measures the international community could take beyond the sanctions already imposed on 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."

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.

As a result of the deteriorating security situation, the government of Canada said Friday that all of its citizens should leave Syria immediately and refrain from travelling there

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, Assad's regime has cracked down on protesters leading movements similar to those that have ousted other Arab autocrats this year.

Meanwhile, activists said Friday that Syrian security forces have opened fire on protesters in three different parts of the country, killing at least seven.