The White House says President Barack Obama and British Prime Minister David Cameron are discussing the need for more countries to contribute humanitarian aid to help the people of Syria and his concerns about the "increasingly dire humanitarian situation" in the Arab country.

The White House says Obama and Cameron spoke by phone Wednesday. White House officials say the president expressed his concerns on the need for more countries to contribute to Syrian humanitarian appeals. The two leaders also talked about ways the international community can help those displaced by the conflict, pressure the regime of President Bashar Assad (bah-SHAR' AH'-sahd) and support the opposition.

The U.S. has provided humanitarian relief to the Syrian rebels and tried to help the opposition come up with a blueprint for a post-Assad future.