Former Pakistan premier Benazir Bhutto [Images] on Thursday escaped a second bid on her life in 10 weeks when a suicide bomber blew himself up minutes after she left the venue of an election rally in the garrison city of Rawalpindi, killing at least 20 people and injuring many others.

Police and leaders of Bhutto's Pakistan People's Party said she was safe and had been driven away from Liaquat Bagh, the venue of the meeting.

Witnesses said a man rushed towards Bhutto's car as she was leaving the sprawling ground, where she had addressed thousands of PPP supporters, and blew himself up.

Rahman Malik, the PPP chairperson's security advisor, said some persons fired at Bhutto's vehicle before the suicide attacker blew himself up.

She evaded the bullets by ducking, he said.

Several people who were around her car were blown to pieces. A television reporter at the scene said the suicide bomber's head was found almost 70 feet from the site of the blast.

Eyewitnesses said body parts were strewn across the area. Ambulances rushed the injured from the spot to nearby hospitals.

Police officials said it was a suicide attack in which at least 20 people were killed and many others injured.

PPP spokesperson Farahtullah Babar said Bhutto's vehicle was about 50 metres away from where the blast occurred.

"She had just crossed the gate when we heard a deafening sound. We could feel its impact but by the grace of God she is safe," he was quoted as saying.

This was the second suicide attack on Bhutto since she returned to Pakistan from exile. Nearly 140 people were killed in two suicide blasts during her homecoming rally in Karachi on October 19.

PML-N chief Nawaz Sharif, who was also campaigning in Rawalpindi, condemned the suicide attack.