Presidential contender Donald Trump has come under attack at a Republican debate, hours after being hammered by some of the party's veteran politicians.

The front-runner in the race to be the party's nominee took to the stage in Detroit with rivals Marco Rubio and Ted Cruz keen to make their mark.

Rubio said Trump deserved to be attacked because he had mocked others.

Many Republicans fear Trump would lose November's presidential election.

The debate hosted by Fox News began with Trump being asked about an attack earlier in the day by Mitt Romney, the 2012 nominee, who accused the businessman of bullying, greed and misogyny.

Calling him a "phony" and a "fraud", the former standard-bearer of the party said Trump's policies - like the deportation of undocumented migrants and banning Muslims from entering the US - would make the world less safe.

On the debate stage, Trump dismissed the criticism because Mr Romney was a "failed candidate", but he immediately found himself on the defensive from Mr Rubio.

The Florida senator said he was "not going to turn over the conservative movement to someone who thinks the nuclear triad is a rock band from the 1980s".

(BBC)