WASHINGTON - US President Barack Obama spoke to British Prime Minister David Cameron about the situation on Ukraine, the White House said on Wednesday.

The two leaders welcomed the military observer mission being undertaken by Organization for Security and Cooperation in Europe (OSCE) at the request of the Ukrainian government, the White House said in a statement.

The United States and 14 other participating states of OSCE on Tuesday formed a military observer mission intended to monitor the situation in Ukraine's Crimea region and the team planned to leave within 24 hours.

Obama and Cameron also discussed support for the government of Ukraine as it works to stabilize its economy and makes preparations for elections in May, the statement said, adding that the leaders agreed to stay in close contact in the days ahead.