Dhaka - Rescue workers discovered another mass grave inside the headquarters of Bangladesh's border guards Saturday, two days after the rebel paramilitary soldiers surrendered, officials said.

The search teams retrieved 10 more mutilated bodies of army officers and their relatives from the second mass grave, raising death toll in the Wednesday's mutiny to 72.

"The second mass grave is discovered beside the Bangladesh Rifles (BDR) training centre," said an officer of the fire service and civil defence department.

He added that the body of the wife of the slain BDR chief Major General Shakil Ahmed was also among the victims.

On Friday, rescue workers retrieved 38 bodies from one mass grave inside the compound.

They also seized arms, ammunition and hand grenades left by the rebel soldiers scattered at different locations inside the 2.6-square-kilometre central Dhaka compound.

Bangladesh has been observing a three-day mourning period starting Friday as a mark of respect to slain army officers.

The government announced that mutineers who have brutally killed the army officers will be tried under a special court.

"The general amnesty announced by the prime minister does not mean that those who took part in killing, mutiny, arson and other heinous activities will be pardoned," Lieutenant General Muhammad Abdul Mubin said.

Mubin, the principal staff officer of the army, read out a written statement issued after a meeting between Prime Minister Sheikh Hasina Wazed and army chief Moeen U Ahmed late Friday.

"Those who committed such barbaric and brutal acts cannot be pardoned and will not be pardoned," Mubin said.

"In order to ensure a speedy trial, the government will form a special tribunal and surely give exemplary punishment [to those found guilty]," the general added.

Police meanwhile launched a drive to arrest mutineers who fled the headquarters after the rebellion, despite the prime minister offering a general amnesty. The previously arrested mutineers are being quizzed by the intelligence units.

Prime Minister Hasina appointed a high-powered committee to launch an investigation into the mutiny, headed by Home Affairs Minister Sahara Khatun.

The rebellion which ended late Thursday with the surrender of the mutineers, 35 hours after rebelling soldiers opened fire on their commanders Wednesday morning at an annual meeting to allow soldiers to air their grievances to their officers.

Several hundred enlisted men, enraged over a pay dispute and alleged repression and corruption by the commanders of the 67,000-strong force, took the officers hostage and then took control of the headquarters. (dpa)