SEVERAL thousand Islamist supporters of deposed Egyptian President Mohamed Mursi have marched through downtown Cairo calling for his reinstatement and denouncing the army general who led his overthrew.

The protest yesterday took place as international envoys stepped up talks with leaders of both sides of the crisis in a bid to find a political solution and avert further bloodshed.

Marchers chanted "Mursi, Mursi" and "We are not terrorists", and waved picture of the ousted leader.

Some sprayed graffiti on walls and statues calling army chief General Abdel Fattah al-Sisi, who led the overthrow of Mursi on July 3, a murderer and a traitor.

The protesters, nearly all men, marched 10 abreast and stretched back several blocks. Security forces made no immediate attempt to disperse a crowd estimated by reporters at several thousand strong.

The protest showed tension is still running dangerously high in Egypt more than a month after Mr Mursi's removal despite the international mediation effort by the United States, the European Union, Qatar and the United Arab Emirates.

Mr Mursi became Egypt's first freely-elected president in June 2012, 16 months after the overthrow of strongman Hosni Mubarak, who had ruled for nearly 30 years.

But fears that he was trying to establish an Islamist autocracy coupled with a failure to ease economic hardships afflicting most of its 84 million people led to huge street demonstrations on June 30, triggering the army move.

The international mediation effort has so far helped to contain further conflict between Mr Mursi's backers and the security forces but has yet to broker a solution.

Thousands of Mursi supporters remain camped out in two Cairo sit-ins, which the government has declared a threat to national security and pledged to disperse. The army-backed interim government said on Sunday it would give mediation a chance but warned that time was limited.

Almost 300 people have been killed in political violence since Mr Mursi's overthrow, including 80 shot dead by security forces in a single incident on July 27. Mr Mursi and much of the leadership of his Muslim Brotherhood are in custody.

Marchers halted outside the office of the public prosecutor, whom they denounced as politically-biased.

In anti-Mursi demonstrations at the same place before his overthrow, protesters had demanded the removal of his appointee to the office, accusing him of ordering arrests of his opponents.

One protester, Mohamed Mustafa, 28, a Cairo University student, said: "Our president is Mohamed Mursi. He will be back. He will complete his presidency. Day after day we stay in Cairo. This is fight is not over. Mursi will return."

Mahmoud Isuafi, a businessman from the Nile Delta city of Mansoura, held a Koran in one hand and a picture of Mr Mursi in the other.

"The military came and stole our country, they stole everything," he said. "I want democracy.

"Where is my vote? I can no longer elect my leader so I protest instead."

International envoys, including US Deputy Secretary of State William Burns, yesterday visited senior Muslim Brotherhood official Khairat El-Shater at Tora prison, south of Cairo.