Governor enters US president race

Mr Richardson took senior posts in the Clinton administration

The governor of the US state of New Mexico, Bill Richardson, has announced he will campaign for the Democratic Party's presidential nomination.

Mr Richardson, a former US envoy to the UN, said he was standing because he could "bring people together to tackle our problems at home and abroad".

He had already said he would run, but election rules stopped him from formally declaring his candidacy.

New York Senator Hillary Clinton is favourite for the Democrat nomination.

Mr Richardson, who is the eighth Democrat to declare himself a contender, was envoy to the UN and later secretary of energy under President Bill Clinton.

Mr Richardson said his experience of high-level diplomacy set him apart from other Democratic candidates.

"There are a lot of candidates in this race with good ideas," he said in a press conference in Los Angeles.

"But coming up with a good idea is only half the job. The other half is bringing people together to get it done."

The 59-year-old is aiming to become the country's first president from a Hispanic background.