* Largest mass death sentence in modern history - lawyer
* Crackdown on Brotherhood since Mursi's overthrow
* Defendants held during clashes in southern province (Adds quote from relative, background)
By Asma Alsharif
CAIRO, March 24 (Reuters) - An Egyptian court sentenced 529 members of the outlawed Muslim Brotherhood to death on charges including murder on Monday, a defence lawyer said, in a sharp escalation of a crackdown on the movement.
The ruling was the biggest mass death sentence handed out in Egypt's modern history, lawyers said.
Turmoil has deepened since the army overthrew Egypt's first freely elected president, Mohamed Mursi of the Muslim Brotherhood, in July. Security forces have killed hundreds of Brotherhood members in the streets, and arrested thousands.
Most of the defendants at Monday's hearing were detained during clashes which erupted in the southern province of Minya after the forced dispersal of two Muslim Brotherhood protest camps in Cairo on August 14.
Islamists have also stepped up attacks on the police and army since Mursi's ouster, killing hundreds and carrying out high profile operations against Interior Ministry officials.
"The court has decided to sentence to death 529 defendants, and 16 were acquitted," lawyer Ahmed al-Sharif told Reuters. The ruling can be appealed.
The charges against the group, on trial in Minya since Saturday, include violence, inciting murder, storming a police station, attacking persons and damaging public and private property.
"This is the quickest case and the number sentenced to death is the largest in the history of the judiciary," said lawyer Nabil Abdel Salam, who defends some Brotherhood leaders including Mursi.
State television reported the sentences without comment. A government spokesman did not immediately respond to calls.
Only 123 of the defendants were present. The rest were either released, out on bail or on the run.
"When the trial starts on Saturday and it is just a procedural hearing, and the judge doesn't listen to any lawyers or witnesses and doesn't even call the defendants, you are before a group of thugs and not the judiciary," Walid, a relative of one of the defendants, said by phone.
It was not possible to confirm his account of the proceedings independently.
The government has declared the Brotherhood a "terrorist" group. The Brotherhood says it is committed to peaceful activism.
Analysts say some of its members could turn violent if the state keeps up pressure on the movement, which won the vast majority of elections since an army-backed popular uprising toppled autocrat Hosni Mubarak in 2011.
Egyptian authorities make no distinction between the Brotherhood and hardcore militant groups based in the Sinai peninsula who pose a major security challenge to the state despite army offensives against their fighters.
Mursi and other top Brotherhood leaders, who are on trial on a range of charges, accuse the military of staging a coup and undermining democracy. (Reporting by Asma al-Sharif; Writing by Michael Georgy; Editing by Andrew Heavens)