US President Barack Obama has arrived in the UK, the second stage of his four-nation trip through Europe.

US President Barack Obama and first lady Michelle Obama arrive at the Dublin Airport.

He arrived in London a night earlier than schedule due to the Icelandic volcanic ash cloud. The Obamas will enjoy a state dinner and stay at Buckingham Palace, with Queen Elizabeth the Second as host.

But Obama also will confront difficult problems as he and Prime Minister David Cameron are expected to review the NATO action to help end conflict in Libya. They will also discuss Western policy towards unrests in the Arab world. Earlier, Obama announced the formation of a new joint US-British national security council.

It's designed to allow the two countries to work more closely together and share intelligence on long-term security challenges, particularly in the Middle East and Afghanistan. Obama will then travel to France, to meet the heads of leading industrial nations, before ending his European trip with a visit to Poland.