Updated

The U.N. refugee agency says the number of Syrian refugees has surpassed the 1.5 million mark.

Agency spokesman Dan McNorton says that since this figure reflects only those who have registered with authorities, it "sadly means the actual number is much higher."

He told reporters Friday that the agency has registered close to 1 million refugees just since the start of this year — from a country that had a population of 23 million — but many more Syrians have not registered due to safety and other concerns

He says that conditions have deteriorated rapidly in Syria during the past four months when compared to the previous 20 months of the conflict.

Most of the Syrians are fleeing to Jordan or Lebanon, each of which has more than 470,000 registered refugees.