Supporters of rival parties in Iran have taken to the streets for a fourth day, amid increasing hostility over the country’s disputed presidential ballot.Reformist opposition supporters again defied the government and marched in the centre of the capital, denouncing recent elections as rigged. The supporters of reformist ex-prime minister Mirhossein Mousavi are out on the streets despite shots being fired at a rally yesterday. Seven protesters died and several others were wounded. Supporters of re-elected President Mahmoud Ahmadinejad are also holding a mass rally, but in a different part of the capital. Mousavi told his supporters to stay away from the Ahmadinejad protest, saying he wanted to protect them from possible violence.