CAIRO: Egypt announced a criminal investigation on Saturday against deposed Islamist President Mohamed Mursi, with prosecutors saying they were examining complaints of spying, inciting violence and ruining the economy.

Egypt's first freely elected leader has been held at an undisclosed location since the army removed him from power on July 3, but has not yet been charged with any crime. In recent days, Washington has called for him to be freed and for the authorities to stop arresting leaders of his Muslim Brotherhood.

The public prosecutor's office said in a statement it had received complaints against Mursi, eight other named Islamist figures including the Brotherhood's leader, Mohamed Badie, and others it did not identify.

The military says it deposed Mursi in a justified response to popular demand after millions of people demonstrated against him. The Brotherhood says it was a coup that reversed democracy.

Turmoil in the most populous Arab state has alarmed the United States and other Western donors. Egypt straddles the Suez Canal and signed a U.S.-brokered peace treaty with Israel in 1979.

Complaints such as those against Mursi are a first step in the criminal process, allowing prosecutors to begin an investigation that can lead to charges. Announcing the step was unusual: typically prosecutors wait until charges are filed.

The prosecutors did not say who had made the complaints. Egyptian law allows them to investigate complaints from police or any member of the public.

Badie and several other Brotherhood officials already face charges for inciting violence that were announced earlier this week, but few of them have been arrested.

Asked about the announcement of criminal investigations against Mursi, Badie and others, U.S. State Department spokeswoman Jen Psaki said, "I can't speak to the specifics of this investigation, but generally speaking, we have made clear the need to follow due process, respect the rule of law, and avoid politicized arrests and investigations."

BROTHERHOOD REJECTS CHARGES

A senior army official told Reuters the authorities were allowing the Brotherhood figures to remain at large in part so that they could monitor their activities and collect evidence against them to ensure that any case was watertight.

"We will leave them to do their talking and protests and we are sure at the end everything will be resolved smoothly and legally," said the official, who asked not to be identified.

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."

Mursi's Brotherhood called on Saturday for more mass demonstrations after large protests broke up peacefully before dawn, ending a week in which at least 90 people were killed.

The Brotherhood, which has maintained a vigil near a Cairo mosque since before the army removed Mursi on July 3, has said it will not leave the streets until he is restored to power.

Tens of thousands turned out on Friday for what the Brotherhood called a "day of marching on". Large crowds of supporters dispersed early on Saturday, although a few hundred marched again after nightfall towards the defense ministry.

Mursi's opponents say these demonstrations are still much smaller than the ones that brought him down. However, the Brotherhood has shown its organizational muscle by keeping its vigil running into a third week and bringing in coachloads of supporters from the provinces during the Ramadan fasting month.

Senior Brotherhood figure Essam el-Erian, one of those who faces arrest, called on his Facebook page for more demonstrations on Monday. "Egypt decides through the ballot box, through protests, mass marches and peaceful sit-ins," he said.