GENEVA: More than 4 million people inside Syria are in desperate need of aid, up sharply from 2.5 million in September, the U.N.’s humanitarian agency said Tuesday.

“We are watching a humanitarian tragedy unfold before our eyes,” Valerie Amos, the U.N. undersecretary-general for humanitarian affairs and emergency relief coordinator, told reporters in Geneva.

A graphic from her office showed how the need for humanitarian aid had spiraled from March last year, when some 1 million people were listed, to 2.5 million in September and 4 million by January 2013.

She described the situation in the war-torn country as “devastating.”

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

Earlier Tuesday, the U.N.’s refugee agency said the number of Syrians who had fled their conflict-ravaged homeland now topped 850,000.

“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 said.

Amos added that more than 250,000 Syrians had fled over a two-month period.

Only a year ago, the United Nations said 33,000 Syrians had fled the conflict that erupted in March 2011 as the regime of President Bashar Assad launched a 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.