Al-Qaeda chief Ayman al-Zawahiri's brother is to stand trial with 67 others for forming a "terrorist group" and plotting attacks after Islamist president Mohammed Mursi's ouster.

Mohammed al-Zawahiri was arrested last August, a month after Mr Mursi's ouster by the army, and has been called to go on trial by the state prosecutor.

The military-installed authorities have since launched a crackdown against Mr Mursi's supporters that has left more than 1,400 people dead and thousands jailed.

Mr Zawahiri and the other suspects are accused of having set up an "Al-Qaeda-linked terrorist group" that plotted attacks against government installations, security personnel and members of Egypt's Christian minority, state news agency MENA said.

The group was seeking to "spread chaos and undermine security" across Egypt, it said.

MENA did not say whether the group had actually carried out any attacks, nor did it give a date for the trial.

It said 50 of the accused were in custody, while others are on the run.

Judicial sources said investigations revealed the group had pressed members to go and fight the regime in Syria, but they were ordered to return to Egypt after 30 June 2013.

They were called back to confront Egypt's new authorities following Mr Mursi's ouster, the sources added. 

Mr Mursi was ousted by former army chief Abdel Fattah al-Sisi after millions took to the streets on 30 June demanding his resignation.

Mr Sisi is now running for president and is expected to win an election on 26-27 May .

Judicial sources said Mr Zawahiri was being charged with having formed the group, armed its members, and trained them in manufacturing explosives and planting bombs.

They said the authorities had evidence that the group's members were trained at secret locations in the Nile Delta city of Sharqiya and in Cairo's Matareya and 6 October districts.

Since Mr Mursi's ouster, Sharqiya has been hit by frequent militant attacks on security forces, while violent clashes in Matareya and 6 October have pitted  the Islamist's backers against police.

The authorities have regularly accused Morsi's outlawed Muslim Brotherhood of financing radical Islamists linked to Al-Qaeda.

Mr Zawahiri himself, who is an Egyptian national, was detained after being freed in the 2011 revolt that ousted Hosni Mubarak.

Egypt has been hit by a string of bombings and shootings targeting security forces since Mr Mursi's overthrow.

The government says almost 500 people, mostly policemen and soldiers, have died in the attacks.

Most of the attacks have taken place in the lawless Sinai Peninsula, but the jihadists have increasingly targeted police in the capital and in the Nile Delta to the north.

The deadliest attacks have been claimed by Sinai-based Al-Qaeda inspired group, Ansar Beit al-Maqdis, but the authorities have blamed the blacklisted Brotherhood.