LONDON — British Prime Minister David Cameron’s office says he has cut short his summer vacation to lead the response to the escalating London riots — with violence and looting occurring for a third day across the capital.

Youths set fire to shops and vehicles in a host of areas of London — which will host next summer’s Olympic Games — and clashed with police in the nation’s central city of Birmingham, as authorities struggled to halt groups of rampaging young people.

Cameron’s office said he was flying to London on tonight, cutting short a family holiday in Italy, and would lead a meeting of the government’s crisis committee on Tuesday as police and lawmakers seek to quell the violence.