GENEVA: The number of Syrians who have fled their conflict-ravaged homeland has topped 850,000, the UN refugee agency said Tuesday.

"As of the 17th of February, we have over 850,000 Syrian refugees who are awaiting registration or have been registered," agency spokesman Babar Baluch told reporters in Geneva.

Only a year ago, the United Nations said 33,000 Syrians had fled the conflict which erupted in March 2011 as the regime of President Bashar al-Assad launched a bloody crackdown on protests.

The United Nations has warned that refugee numbers could reach 1.1 million within months in what has become an increasingly radicalised civil war in the nation of almost 21 million.

Most of the anti-Assad rebels are Sunni Muslims, while the ruling clan and many of its most fervent supporters are from the Alawite minority, an offshoot of Shiite Islam.

Most of the refugees have fled to neighbouring Lebanon, Jordan, Turkey and Iraq.

The United Nations says at least 70,000 people have been killed in the conflict, while some 2.5 million have been displaced by the fighting but remain in Syria.