Republican 2012 presidential nominee Mitt Romney says he will not make another White House run in 2016, following weeks of speculation he would mount another campaign.

"After putting considerable thought into making another run for president, I've decided it is best to give other leaders in the party the opportunity to become our next nominee,"

Romney said during a conference call with supporters, broadcast live by CNN on Friday.

"I believe that one of our next generation of Republican leaders, one who may not be as well known as I am today, one who has not yet taken their message across the country, one who is just getting started, may well emerge as being better able to defeat the Democrat nominee," Romney said.

"In fact, I expect and hope that to be the case."

The announcement essentially quiets three weeks of speculation about Romney mounting a third presidential campaign, after he told donors in New York that he was still seriously interested in the White House.

 

Romney told supporters on Friday that it was "unlikely" that circumstances would change his mind, and that he was not taking donations or hiring a campaign team.

Romney, a former two-time governor of Massachusetts who amassed a vast fortune as a venture capitalist and businessman, said in speeches this month that the Republican Party needed to make income inequality and poverty alleviation key planks in the presidential race.