Rawalpindi, 4 Feb. (AKI) - At least six people were killed in a suicide bombing which targeted a military bus in the Pakistani city of Rawalpindi on Monday.

Another 20 people are reported to have been injured in the attack believed to have been caused when a bomber crashed into the bus.

Rawalpindi has been the target of several violent attacks in the past year, including the brutal assassination of opposition leader and former prime minister Benazir Bhutto, killed in a political rally there on December 27.

Several vehicles were damaged in the blast which destroyed the bus near the army headquarters in the garrison city.

Rawalpindi has been at the centre of several attacks in the past six months, which have claimed dozens of lives.

A suicide bomber killed seven people near the office of President Pervez Musharraf on October 30.

Authorities blamed Monday's attack on pro-Taliban militants operating out of Pakistan's tribal region of Waziristan, but no one claimed responsiblity for the bombing.