Jordan on Thursday launched an urgent aid appeal to cope with what officials called a refugee crisis sparked by the arrival of 22,000 Syrians in one week, according to dpa. Foreign Minister Nasser Judeh said Jordan had called for urgent support from international donors to help it deal with an "unprecedented" number of Syrian refugees. A record 6,000 crossed on Tuesday alone. Earlier this month, Jordan said it hosted 285,000 Syrian refugees, more than half of those displaced by the conflict since March 2011. The influx has pushed Jordan's lone Syrian refugee camp well beyond its 60,000-person capacity. Jordanian officials say they need urgent funds to build two further camps to host an additional 50,000 refugees. Relief officials say their humanitarian response is being undermined by underfunding. The United Nations has not yet secured more than 5 per cent of a record 1 billion dollars in aid it appealed for in December. Abu Hani al-Darawi, a coordinator with the rebel Free Syrian Army, said aerial attacks by Syrian government troops on villages and other urban centres have driven tens of thousands of Syrians south toward the Jordanian border, where some 15,000 have amassed. "With missiles falling in every town and every village, nowhere in Syria is safe," al-Darawi said. "For many Syrians, the choice now is either Jordan or death." Despite pledging to maintain an open border policy, Jordan has indicated in recent weeks that it will close the frontier should Syria tip into "chaos." Government spokesman Samih Maaytah said Jordan was to keep the borders open despite the dramatic influx. He added that closing the border would be a "last resort." Jordan has said the rapidly growing refugee population cost the country some 600 million dollars in 2012 - a figure forecast to reach 800 million dollars in 2013 should the crisis persist.