U.S. President Barack Obama on Saturday called British Prime Minister David Cameron, discussing the impact of the oil spill in the Gulf of Mexico, and a range of world issues.

According to the White House, Obama and Cameron reiterated during their 30-minute call that BP must do all it can to respond effectively to the situation in the Gulf, which was termed by the White House as the biggest environmental disaster that the country has ever faced.

The White House readout didn't provide further details about the discussion on the oil spill, but the British authorities said Cameron expressed his sadness at the situation.

The two leaders also discussed the situation in Afghanistan, the United Nations Security Council's sanctions on Iran, and economic issues, including preparations for the G-8/G-20 meetings later this month.

Obama affirmed his commitment to the special and historic relationship between the two countries, and thanked Cameron for his commitment on the broad range of issues on the two countries' shared agenda.