Jordan's prime minister says it will be "very, very difficult" to keep absorbing Syrian refugees unless Jordan receives significant economic aid, including budget support and new trade arrangements.

Abdullah Ensour made the link between refugee admissions and foreign aid in unusually blunt comments Saturday. He spoke ahead of next week's Syria aid conference where pledges of some $9 billion are sought for 2016 to alleviate the fallout from the five-year-old conflict.

Most of the Syria war refugees, about 4.3 million, live in overburdened regional host countries, such as Jordan, which has taken in 630,000.

Jordan and Lebanon initially allowed large numbers of Syrians to enter their territories, but have severely tightened restrictions. About 17,000 Syrians have amassed in a remote desert area on the Jordanian border, awaiting permission to enter.