Groups aiding Syrian refugees ask donors to pay up, warning they'll have to cut basic services

More than 200 groups helping 3.9 million Syrian war refugees are calling on international donors to send promised aid, saying they are fast running out of funds to deliver basic services.

The groups said Thursday that just $1 billion out of $4.5 billion pledged for 2015 has been received.

The head of the U.N. refugee agency, Antonio Guterres, says the "massive crisis" requires far more international solidarity and that "dangerously low" funding levels mean basic needs of millions of refugees will likely go unmet.

The aid groups say 1.6 million refugees already had food aid reduced this year, 750,000 children are not attending school and many refugees can no longer afford health services. They say the vast majority of urban refugees in Jordan live below the poverty line.