CAIRO (AP) -- Egypt's chief prosecutor ordered Thursday an investigation into the leaders of the country's opposition after a lawyer accused them of incitement to overthrow the regime of newly elected Islamist President Mohammed Morsi, a prosecution official said.
The order, issued by an appointee of Morsi, is likely to aggravate political tensions that have erupted into street violence, most recently surrounding the newly passed but divisive constitution.
The accusation, filed last month, alleged that Mohammed ElBaradei, a Nobel Prize laureate and former head of the U.N. nuclear agency, along with Amr Moussa, a former foreign minister, and Hamdeen Sabahi, a former presidential candidate, campaigned to seek Morsi's overthrow.
The probe does not necessarily mean charges will be leveled but it is unusual for state prosecutors to investigate such broad charges against high profile figures. The official spoke on condition of anonymity in line with government policies.
Yara Khallaf, a spokeswoman for Moussa, said there were no official charges or summoning for investigation, declining to comment on the accusation.
Emad Abu Ghazi, the secretary general of the opposition party ElBaradei heads, said he had no details about the investigation but that the accusations and probe were "an indication of a tendency toward a police state and the attempt to eliminate political opponents."
Abu Ghazi said the former regime of Mubarak dealt in the same way with the opposition. There was no immediate comment from ElBaradei or Sabahi.
The accusation came during a political crisis over a series of presidential decrees that granted Morsi, Egypt's first elected president, and the committee drafting the disputed constitution immunity from judicial oversight.
The opposition called on Morsi to rescind his decrees and accused him of amassing too much power in his hands. It also asked for the draft constitution to be withdrawn.
The opposition organized a number of massive rallies in protest, including one outside Morsi's palace in which protesters chanted "Leave." It was a common refrain during the protests against former President Hosni Mubarak, who was ousted in a popular uprising last year.
The rally turned violent when supporters of Morsi, who perceived the protest as a threat to his legitimacy, attacked their opponents.
Clashes erupted that turned deadly and were followed by attacks on offices of the Muslim Brotherhood, the main backers of the constitution and from which Morsi hails, and the office of a liberal opposition party, al-Wafd. At least 10 people died in the violence, and the Brotherhood claimed they were mostly its supporters.
Morsi and Brotherhood officials accused the opposition of working to undermine the president's legitimacy, and accused former regime officials of working to topple him.