"The evidence I hold confirms that Egypt is being subject to a vicious conspiracy by some political forces, the extent of which has reached the incitement of protesters to raid the presidential palace and wreak havoc in order to sabotage all measures the president has taken towards achieving stability," he said.
At least six protesters died in clashes between opponents and supporters of President Morsi Wednesday. Supporters of Morsi, who hails from the Muslim Brotherhood, marched on the palace and attacked a sit-in staged by dozens of opponents left over from a mass rally Tuesday at the palace.
Protesters are against the draft constitution Morsi accepted last Saturday and his constitutional declaration of 22 November in which he granted himself immunity from judicial challenge, also shieldling the Islamist-led Shura Council (the upper house of parliament) and the constitution-drafting Constituent Assembly.
President Morsi said during a speech to the nation Thursday night that "investigations and confessions have shown that some of those arrested have connections to political forces. Other armed assailants were paid."
The public prosecution ordered Friday the release of 139 anti-Morsi protesters who had been arrested in Wednesday's clashes.
Abdel-Maqsoud did not say in his statement whether he intends to present the evidence he says he holds to prosecutors.
"The [opposition's] excuse of opposing the constitution is only a cover-up to their target of overthrowing the president. I can confirm that before they withdrew at the last minute, [non-Islamist] members of the Constituent Assembly agreed to 95 per cent of the constitution articles and they all signed to that," Abdel-Maqsoud continued.
Amid ongoing rival protests since the issuance of the 22 November constitutional declaration, President Morsi has called for a national referendum on the constitution 15 December.
President Morsi called on opposition forces to enter talks Saturday, but the latter's most prominent umbrella group -- the National Salvation Front -- has refused negotiations, holding out on its demands that the president cancel the constitutional declaration, call off the referendum and open the draft constitution to fresh deliberations.