Pakistan´s former military ruler Pervez Musharraf, who is on trial for treason, narrowly escaped an assassination attempt as a bomb went off shortly before his convoy was due to pass early Thursday, police said.

The bomb was planted on Musharraf´s route from an army hospital where he has been staying since January to his home on the outskirts of Islamabad.

Nobody was injured and there have so far been no claims of responsibility. "Four kilograms of explosive device planted in a pipeline under a bridge exploded around 20 minutes before the former president was supposed to cross the spot," senior police official Liaqat Niazi said.

He said the former president was taken home via an alternative route. Muhammad Naeem, a spokesman for the Islamabad police, confirmed the incident, saying a bomb disposal squad had cleared the area after the blast.

"Nobody was injured in the blast," he said, adding Musharraf was the intended target.Musharraf, who led Pakistan from 1999 to 2008, returned from self-imposed exile in March last year to fight in general elections but was barred from taking part and has faced a series of legal cases including treason.

The Taliban also vowed to send a squad of suicide bombers to kill him, and security threats have prevented him from appearing at all but two of his treason hearings.

It was the fourth attempt on the ex-general´s life, with the first three occurring while he was in office.