At least 45 people have been killed in Pakistan in a bomb attack in a Shiite dominated part of the country's biggest city, Karachi, 150 others were wounded in the two explosions. The attack comes a week after a bomb blast in the Pakistani city of Quetta killed almost 90 people, most of them Shiites. Mike Wooldridge reports from Islamabad.___________________________________________________________________________________________.Several buildings caught fire and some collapsed. Political and religious leaders have been quick to condemn the attack which follows a wave of sectarian violence affecting particularly Karachi, but other parts of Pakistan too. Sunni Muslim extremists have stepped up attacks against members of Pakistan's minority Shiite community. And bombings in the city of Quetta alone have killed nearly 200 people since the start of this year.