Queen Elizabeth greets Obama at Buckingham Palace

Queen Elizabeth and the Duke of Edinburgh on Tuesday greeted US President Barack Obama and his wife Michelle at the Grand Entrance to Buckingham Palace.
Obama arrived in the UK as part of a four-country European visit to Ireland, England, France, and Poland.
Obama was expected to meet with Prime Minister David Cameron to review NATO action to help end conflict in Libya and Western policy towards uprisings in the Arab world.
He and Cameron will also launch a joint US-British group to tackle national security challenges together.