CAIRO: Egypt's ousted President Hosni Mubarak will face a new trial beginning April 13 on charges related to the killings of protesters during the revolution that forced him from power, a court ruled Sunday.

Mubarak and his former interior minister were each sentenced to life in prison in June for failing to prevent the killing of protesters during the 18-day uprising in 2011 that ended his 29-year rule. In January, an appeals court overturned the sentences and ordered a retrial, raising public anger over what was seen as a shoddy prosecution in the first case.

Critics wanted Mubarak convicted and sentenced to death for directly ordering the brutal crackdown, which killed nearly 900 people.

The retrial is likely to intensify an already tense political atmosphere. It is due to start just over a week before Egypt's parliamentary elections begin, a vote that has deeply polarized the country, still reeling from a turbulent transition.

Mubarak's successor Mohammed Morsi and his government argue that parliamentary elections will help put the country on the right track, enabling him and the legislature to tackle a deteriorating economy.

But the opposition has called for an election boycott and has threatened to escalate an anti-government street campaign. The opposition accuses the Islamist president of failing to seek consensus over critical issues, such as the drafting of the constitution and the elections law.

Opponents accuse him of working to empower his Muslim Brotherhood and ensuring its lock on power.

Meanwhile, popular discontent over the government's performance is already spilling into violent confrontations on the streets and a myriad of work stoppages.

On Sunday, clashes erupted between security forces and protesters in the port city of Port Said, the scene of a civil strike now in its second week. City residents started their strike in anger over the excessive use of police force, which killed over 40 civilians in late January, to demand retribution.

The killings took place during protests that swept the city after a Cairo court passed death sentences against 21 people, mostly from Port Said, for their part in Egypt's worst soccer disaster on Feb. 1, 2012.

The street battles broke out Sunday when word emerged that those sentenced were transferred to prisons outside the city. A police official, speaking on condition of anonymity because he wasn't authorized to discuss the case, said the transfer was necessary to ensure calm before a March 9 court hearing that is expected to confirm the death sentences and issue new verdicts for police officers also charged in connection with the soccer violence.

Protesters set a police vehicle on fire, and pelted the main police station with rocks. Police forces, which had all but vanished from the city after last month's violence, fought off the protesters lobbing tear gas and rocks in a standoff that continued for hours.

In Cairo, die-hard soccer fans of Al-Ahly club, known as Ultras, were also gearing up for the March 9 verdict by staging protests around town that blocked traffic going to the airport, and closed off the area around the central bank.

Most of those killed in the Port Said stadium were Al-Ahly Ultras, and the group is pressing for retribution from Port Said soccer fans as well as security officials.

Meanwhile, in the ancient southern city of Luxor, scores of bazaar owners blocked the roads leading to the famed ancient sites such as the Valley of the Kings, barring tourist buses from getting through in an unprecedented move.

The protesters are demanding the government exempt them from paying rent because of the dismal tourism revenues.

Mubarak, 84, has been in detention since April 2011 and is currently being held in a military hospital.

The issue of those killed during the mass protests that led to Mubarak's ouster is a sensitive one in Egypt, with the families of the victims demanding retribution and compensation. Morsi, promised during his election campaign that he would put former regime officials back on trial if new evidence was discovered.

The proceedings could help resolve unanswered questions over who ordered the crackdown and who executed it. Most security officials were acquitted in separate trials related to the deaths of protesters.

In January, the appeals court ruled that during Mubarak's first trial, the prosecution's case lacked concrete evidence and failed to prove the protesters were killed by the police, indirectly giving credence to the testimony of top Mubarak-era officials that "foreigners" and others were behind the killings between Jan. 25 and Feb. 1, 2011. Critics scoffed at those charges, blaming Mubarak's police and sympathizers.

Authors of a recently concluded confidential report by a fact-finding mission appointed by Morsi told reporters that they have established the use of deadly firearms by the police against protesters.

On Sunday, Judge Samir Aboul-Maati said the retrial before a criminal court will include six other senior security officials who were acquitted in the first trial. Mubarak's two sons and a business associate also will be retried on corruption charges. The sons, onetime heir apparent Gamal and wealthy businessman Alaa, are in jail while on trial for insider trading and using their influence to buy state land at a fraction of its market value.

The business associate, Hussein Salem, was tried in absentia. He is currently in Spain.