Mitt Romney announces bid to be US president in 2012

Former Massachusetts governor Mitt Romney has entered the race to be the Republican candidate for US president in 2012, saying President Barack Obama has "failed America".

Mr Romney blamed Mr Obama for the economic woes frustrating voters, like federal spending and unemployment during a speech in New Hampshire.

The wealthy businessman is the current frontrunner in the Republican field, but can he withstand a challenge from former vice-presidential candidate Sarah Palin?

Mark Mardell reports.