WASHINGTON - US President Barack Obama and British Prime Minister David Cameron on Saturday called for an "immediate halt of all bloodshed and violence" against the protesters in Syria, the White House said.

In a phone conversation, the two leaders discussed the situation in Syria, "reiterating their deep concern about the Syrian government's use of violence against civilians and their belief that the Syrian people's legitimate demands for a transition to democracy should be met," the White House said in a statement.

"They agreed on the need for an immediate halt of all bloodshed and violence against the Syrian people," the statement said, adding the two leaders agreed to closely monitor the actions the Syrian government is taking and consult on further steps in the days ahead.

It said Obama and Cameron also discussed recent developments in the global financial system, Libya and Afghanistan.

Obama spoke to Saudi King Abdullah earlier the day about the situation in Syria, which has been gripped by anti-government protests since mid-March. The Syrian authorities attributed the unrest to terrorist groups and foreign conspiracy.