US President Barack Obama cracked jokes about his origins at the White House Correspondents' Association dinner.

The president used the traditionally light-hearted event to poke fun at conspiracy theorists who question whether he was really born in Hawaii.

Sceptics known as "birthers" have suggested Mr Obama was secretly born outside the United States, which would make him ineligible to run the country.

The president told his audience of journalists and celebrities that there are few things in life harder to find and more important to keep than love, adding: "Well, love and a birth certificate."

He took aim at his own administration too, cracking jokes about Vice President Joe Biden's use of a four-letter word at the signing of the Democrats' historic healthcare bill.

The White House Correspondents' Association was formed in 1914 as a liaison between the press and the president. Every president since Calvin Coolidge has attended the dinner.