Muslim Brothers in military trial

The defendants are understood to face charges relating to membership of a banned organisation, money-laundering and supporting terrorism.

Defence lawyers boycotted the session, protesting that the court did not notify them of the start of the trial.

The Muslim Brotherhood is outlawed, but has traditionally been tolerated.

This is the first time in seven years that members of the Muslim Brotherhood have been tried before a military court.

Key defendant

The main defendant is Khayrat el-Shater, a senior figure said to be the group's strategist and chief financial officer.

"We haven't been officially notified about this trial. The whole thing looks suspicious," a member of the defence team told the Associated Press news agency.

The decision to hold a military trial has been seen as yet another sign of the government's determination to limit the success of the brotherhood, says the BBC's Heba Saleh in Cairo.

The brotherhood is Egypt's most powerful opposition group, and won nearly a fifth of seats in the 454-seat lower house of parliament in 2005.

It has frequently accused the government of carrying out a campaign designed to eliminate it as an effective political force.