Former Pakistan President Pervez Musharraf has addressed retired military officers in a video, released on the eve of his treason trial, calling the cases against him "concocted".

Pakistan's former military ruler said in the video on Tuesday that despite "unnecessary" delays to his trial, he is still expecting justice from the courts.

Authorities defused four small bombs planted near Musharraf's house, where he has spent much of his time under arrest, police said on Monday.

A previous start to the trial was postponed on December 24 after another bomb scare.

Musharraf ruled Pakistan for nearly a decade after taking power in a 1999 coup.

He was forced to step down in 2008 and later left the country in a self-imposed exile.

The former army chief returned in March 2013 hoping to take part in the upcoming elections but immediately faced a barrage of legal problems, relating to his time in office.

The high treason case relates to the state of emergency he imposed in 2007.

Musharraf's supporters have portrayed the charges against him as a vendetta, and his lawyers are challenging the impartiality of the three judges hearing the treason case and the appointment of the prosecutor representing the government.

"Our concern is that a panel of judges has been hand-picked by the executive to put, to put the former president on trial and that is not in compliance with the separation of powers, and that is not in compliance with the rule of law as it is recognised by the international community and particularly by the United Nations system," Toby Cadman, a lawyer, said.

Source: Al Jazeera and agencies