Egypt's ousted president Mohamed Morsi is under a criminal investigation while the a new cabinet is taking shape, officials said Saturday.

Interim Prime Minister Hazem al-Beblawi, an economist, has been trying to form a cabinet mainly comprising technocrats and liberals. Most of the candidates for the 30 portfolios have been identified by Saturday, pending final decisions.

Beblawi said the top priorities of the incoming cabinet would be to restore security, ensure the flow of goods and services and prepare for parliamentary and presidential elections.

Egypt's interim authorities have drafted a "roadmap" to restore full civilian rule with plans for a new constitution and parliamentary elections in about six months, followed by a presidential vote.

Mohamed Morsi, the first freely elected president in Egypt, was removed from power by the military on July 3 after millions of people took to the streets calling on him to step down.

He has been held at an undisclosed location since the ouster. Interim leaders say it was a "safe place, for his own safety."

The public prosecutor's office said Saturday it was looking into complaints against Morsi and other Islamist figures including the Brotherhood's leader Mohamed Badie.

The complaints include spying, inciting violence and ruining the economy, although prosecutors did not say who had made the allegations.

During his one-year rule, Morsi was accused of concentrating power in the hands of the Muslim Brotherhood and letting the economy plunge into chaos.

His supporters say the overthrow was a military coup that reversed democracy. The military says it toppled Morsi in a justified response to popular demand after millions protested against him.

Complaints against Morsi are allowing prosecutors to begin an investigation that can result in charges being brought to court. Badie and several other Brotherhood officials already face charges for inciting violence as announced earlier this week, and five have been arrested.

Brotherhood spokesman Gehad El-Haddad said the charges were absurd and that it was the authorities themselves who were responsible for inciting violence.

"They execute the crime themselves and then they slap it on their opponents. As long as you have a criminal police force and a complicit judiciary, the evidence will appear and the judge will be satisfied. And the media will sell it to the public."

Morsi's Brotherhood called on Saturday for more mass protests a day after tens of thousands of Morsi supporters rallied peacefully in Cairo.

"There will be another mass protest on Monday," said Tareq al-Morsi, a Brotherhood spokesman.

"Egypt decides through the ballot box, through protests, mass marches and peaceful sit-ins," senior Brotherhood figure Essam el-Erian, one of those who faces arrest, wrote on his Facebook page.

At least 90 people have been killed in a week of deadly battles between the army and pro-Morsi supporters.

The United States refuses to say whether it considers the army takeover a "coup", which under U.S. law would require it to cut off aid including around 1.3 billion U.S. dollars a year in military support.

In recent days it has described Morsi's rule as undemocratic because of the vast popular protests against him, but also urged the authorities to release him and stop detaining his followers.

In a telephone call with Saudi King Abdullah bin Abd al-Aziz on Friday, U.S. President Barack Obama expressed "serious concern" about the violence since Morsi's overthrow and underscored the need to return to a democratically elected civilian government, the White House said.

Turmoil since a popular uprising ousted former president Hosni Mubarak in 2011 has wrecked Egypt's economy, scaring away tourists and investors, draining hard currency reserves and making it difficult to import food and fuel, which the government distributes at heavily subsidized prices.

Rich Gulf Arab states Saudi Arabia, the United Arab Emirates and Kuwait, happy at the overthrow of the Brotherhood, have pledged 12 billion U.S. dollars in assistance to shore up Egypt's faltering economy.