Martin O'Malley joins Democratic race for White House

Former Maryland Governor and Baltimore Mayor Martin O’Malley has joined the 2016 US presidential race, challenging Hillary Clinton and Bernie Sanders for the Democratic nomination.

He highlights his record as a social liberal – citing action on tackling income inequality by raising the state’s minimum wage , legalising gay marriage and helping undocumented migrants gain access to education.

But critics say his “zero-tolerance” policies on crime damaged police-community relations.

Baltimore was rocked in recent weeks by riots over the death of Freddie Gray, a young black man, from injuries sustained while in police custody.