Egypt's public prosecutor has ordered former president Mohammed Mursi and 35 other Islamists to stand trial on a range of charges.
They include conspiring with foreign groups to commit terrorist acts in Egypt and divulging military secrets to a foreign state.
The charges levelled against Mr Mursi and other top Muslim Brotherhood members could result in their execution.
Mr Mursi is already standing trial for inciting violence during protests outside the presidential palace a year ago when he was still in office.
He was deposed in July by the army following mass protests against his rule.
In a statement, the prosecutor said the brotherhood had committed acts of violence and terrorism in Egypt and prepared a "terrorist plan" that included an alliance with the Palestinian group Hamas and Lebanon's Hezbollah.
There was no immediate comment from Hamas or Hezbollah.
The charge sheet called it "the biggest case of conspiracy in the history of Egypt".
It accused the brotherhood of carrying out attacks on security forces in North Sinai after Mr Mursi was deposed on 3 July.
It said the brotherhood had hatched a plan dating back to 2005 that would send "elements" to Gaza for military training by Hezbollah and the Iranian Revolutionary Guards.
Upon their return to Egypt, they would join forces with extremist groups in the Sinai Peninsula, it said.
The group exploited the chaos that followed the 2011 uprising that toppled Hosni Mubarak, carrying out attacks on the security forces in North Sinai and elsewhere, the prosecutor said.
The group aimed to establish an "Islamic emirate" in North Sinai were Mr Mursi not declared president.
The prosecutor added that Mr Mursi's presidential aides including Essam El-Haddad, his national security adviser, had leaked secret reports to the Iranian Revolutionary Guards and Hezbollah as a reward for their cooperation.
The Egyptian authorities have launched a fierce crackdown on the Muslim Brotherhood since Mr Mursi was removed from power, killing hundreds of his supporters during protests and arresting thousands more.