Egyptian police on Wednesday fired tear gas into Cairo's Tahrir Square, where several hundred protesters spent the night after a mass rally to denounce President Mohamed Morsi's assumption of expanded powers.

Clashes that have been erupting on streets just off Tahrir spilled into the square Wednesday morning, with canisters falling into the crowd forcing protesters to run and sending clouds of tear gas over the tents housing the demonstrators, television images showed.

Tens of thousands packed Tahrir Square on Tuesday to protest a power grab by Mohamed Morsi, piling pressure on Egypt's Islamist president as he faces his most divisive crisis since taking power in June.

The huge turnout in the iconic square in the heart of Cairo, as well as in the Mediterranean city of Alexandria and most of Egypt's 27 provinces, marked the largest mobilization yet against the president.

One person was killed and at least 40 others were wounded in clashes Sunday between supporters and opponents of Egyptian President Mohamed Morsi in the Nile Delta, south of Egypt's second city Alexandria, amid a show of strength on the streets between the two rival camps.

"Islam Fathi Mohammed was killed" in clashes outside the Muslim Brotherhood headquarters in the town of Damanhour, one of the movement's leaders, Jamal Hichmat, told Agence France Presse.

An office of Arab satellite broadcaster Al-Jazeera in the Egyptian capital was firebombed on Wednesday, a security official said, as protesters clashed near the downtown Tahrir Square.

"Unknown assailants" lobbed Molotov cocktails at the office which overlooks Tahrir, "causing a big fire which rescue services are working to put out," the official said.

An Israeli official landed in Cairo on Sunday for Egypt-mediated truce talks with Hamas to end the Gaza conflict, Egyptian security officials said.

The official landed in a small plane at 1100 GMT and was quickly escorted away by intelligence personnel, the security officials said.

Maronite Patriarch Beshara al-Rahi attended on Sunday the enthronement of the new Coptic pope in Cairo ahead of the Nov. 24 ceremony that would officially appoint him as a new cardinal in the Catholic church.

The enthronement of Bishop Tawadros was held at Cairo's St. Mark's Cathedral.

Qatar is to give Egypt $10 million to help treat Palestinians wounded in Israeli air strikes on the neighboring Gaza Strip, state news agency QNA reported on Saturday.

The oil-rich Gulf nation will also send emergency aid including medical equipment and medicines to Hamas-controlled Gaza, it said.

At least five people were killed on Saturday and dozens injured when two trains collided south of the Egyptian capital, a security source said.

One of the trains was heading for Cairo from Fayyoum and the other was traveling in the opposite direction. They collided between the villages of Sila and Nassiriya.

Russian Foreign Minister Sergei Lavrov met in Cairo on Sunday with Arab League chief Nabil al-Arabi for talks about the Syrian conflict, agreeing on the need to move forward but finding little common ground.

"We discussed the situation in Syria... reviewing what has been done so far and if there is any way to move forward. And let us be clear, there wasn't any agreement on anything," al-Arabi told a joint news conference.

Buying a pair of trousers at one in the morning has never been a problem in Cairo, but a new government proposal to slash trading hours could effectively pull the plug on the city that never sleeps.

Minister of Local Development Ahmed Zaki Badr has warned that the government is considering legislation that would see shops close at 10 pm and restaurants at midnight. "Tourist establishments" with a special license such as hotels and bars, would be exempt.