A retrial of former President Hosni Mubarak, jailed for life for his role in the deaths of protesters in 2011, is to open on April 13, Egypt's official MENA news agency reported on Sunday.

Mubarak, former interior minister Habib al-Adly and six top security chiefs will be retried on orders of the Court of Cassation, Egypt's top appeals court, over the hundreds of killings during the 2011 uprising which ousted him from power.

Egyptian protesters stormed a police building in the city of Mansura on Saturday, amid renewed clashes after a demonstrator's death overnight, the official MENA news agency reported.

They attacked a building that formerly housed the now-relocated regional police headquarters, but where police still have offices.

U.S. Secretary of State John Kerry said on Saturday that Egypt's crumbling economy must "get back on its feet," while on a visit to Cairo aimed at pressing deeply divided parties to reach a political consensus.

"It is paramount, essential, urgent that the Egyptian economy gets stronger, that it gets back on its feet," Kerry told a meeting of business leaders.

Egyptian protesters torched a police station in Port Said on Saturday as US Secretary of State John Kerry landed in Cairo to push for a way out of the country's political impasse.

The interior ministry said about 500 protesters threw stones and petrol bombs at the police station, setting it on fire, and then blocked fire engines from reaching the blaze.

U.S. Secretary of State John Kerry arrived in Cairo on Saturday for talks with the leaders of Egypt and their opposition, amid political turmoil and a crippling economic crisis.

Kerry, who arrived from Turkey, is due to hold talks with Islamist President Mohammed Morsi, as well as political parties, business leaders and civil society groups during his two-day visit.

One person was killed and dozens injured in overnight clashes between police and protesters in Egypt's Nile Delta city of Mansura, a security official told Agence France Presse on Saturday.

A week of demonstrations in Mansura turned violent late on Friday when police fired tear gas at protesters outside the governorate headquarters, witnesses said.

Bearded policemen were among some 200 people who took to the streets of Cairo on Friday to demand that policemen suspended for growing beards, worn by pious Muslims, be reinstated.

"We are protesting because we were suspended due to our beards," policeman Mohammed Salah, who took part in the demonstration, told Agence France Presse.

Egyptian police fired tear gas on Friday to disperse Muslim protesters outside a church in southern Egypt after claims that a women who converted to Christianity was hiding in the church, a security source.

The police acted after the protesters pelted them with stones in the town of Kom Umbo, the source said.

Around 50 Egyptian Christians suspected of trying to convert Muslims have been arrested in the eastern city of Benghazi on illegal immigration charges, a Libyan security official said on Friday.

"Forty-eight Egyptian traders who worked in the Benghazi municipal market have been arrested based on reports of suspect activities," the source told Agence France Presse.

The Grand Imam of al-Azhar, the top religious authority for Sunni Muslims, on Wednesday urged Islamist militants in the Philippines to free a reporter with al-Arabiya news channel seized in June.

Sheikh Ahmed al-Tayeb called upon kidnappers to "revert to right and religious principles... which stress that kidnapping and terrorism are prohibited," in a statement released by his office in Egypt's capital.