An Egyptian court handed down a death sentence on the leader of the Muslim Brotherhood and 682 supporters, intensifying a crackdown on the movement that could trigger protests and political violence ahead of an election next month.

A death penalty for Mohamed Badie, the Brotherhood's general guide, will infuriate members of the Brotherhood which has been the target of raids, arrests and bans since President Mohammed Morsi was forced from power by the military in July.

The movement says it is committed to peaceful activism. But some Brotherhood members fear pressure from security forces and the courts could drive some young members to violence against the movement's old enemy the Egyptian state.

In a separate case, the court handed down a final capital punishment ruling for 37 others. The 37 death sentences were part of a final judgment on 529 Muslim Brotherhood supporters who were sentenced to death last month. The remaining defendants were sentenced to life in jail, judicial sources said.

Death sentence recommendations in the case involving Badie will be passed on to Egypt's Mufti, the highest religious authority. His opinion is not legally binding and can be ignored by the court.

Mass trials in the biggest Arab state have reinforced fears among human rights groups that the military-backed government and anti-Islamist judges are using all levers of power to crush dissent.

"The decisions are possibly the largest possible death sentences in recent world history. While they're exceptional in scale, they're certainly not exceptional in kind," said Sarah Leah Whitson, executive director for Middle East and North Africa at Human Rights Watch.

"It seems that these sentences are aimed at striking fear and terror into the hearts of those who oppose the interim government including the interim government."

The rulings can be appealed. Many defendants are on the run.

Nevertheless, the cases have raised new questions about Egypt's stumbling political transition three years after an army-backed popular uprising ousted autocrat Hosni Mubarak and raised hopes of a robust democracy.

Pro-democracy movement banned

A pro-democracy movement that helped ignite the uprising that toppled Mubarak in 2011 was banned by court order on Monday, judicial sources and the website of the state-run Al-Ahram newspaper said.

The ruling banning the activities of the April 6 movement follows the imprisonment of three of its leading members last year on charges of protesting illegally. The charges against April 6 included "damaging the image of the state", according to the Al-Ahram report.

As soon as word spread of the death sentences, relatives of the defendants screamed and cried outside the court in the southern town of Minya.

Some blamed Abdel-Fattah el-Sissi, the general who deposed President Morsi of the Brotherhood last July. He is expected to easily win presidential elections next month.

"Sissi is ruling like a king" and "May God punish you for what you did" some people chanted.

Egypt's biggest political party until last year, the Brotherhood has been outlawed and driven underground.

It has vowed to bring down the government through protests, even though a security campaign has weakened the movement, which is believed to have about one million supporters in the country of 85 million.

Despite decades of repression under one Egyptian ruler after another, the Brotherhood has managed to survive, winning over Egyptians with its social networks and charities.

This time, it lost considerable popular support after Morsi was accused of trying to acquire unlimited powers and mismanaging the economy during his year in office.

But authorities still see the movement as a major threat.

Badie was charged with crimes including inciting violence that followed the army overthrow of Morsi.

Hundreds of Brotherhood supporters and members of the security forces have been killed in political violence and thousands of Islamists and some secular dissidents jailed by authorities since then.