President Hosni Mubarak on Saturday, in response to violent nationwide protests, appointed intelligence chief Omar Suleiman as Egypt's first vice president in 30 years, and also appointed Aviation Minister Ahmad Shafiq as the new prime minister.

"Omar Suleiman has been sworn in as deputy to President Hosni Mubarak," the MENA news agency reported.

Suleiman, 74, has been the director of the Egyptian General Intelligence Services since 1993, a position in which he played a prominent public role in diplomacy, including in Egypt's relations with Israel and the United States.

As Egypt's intelligence chief, Suleiman was in charge of the country's most important political security files.

Also on Saturday, Mubarak appointed Aviation Minister Ahmad Shafiq as the new prime minister and asked him to form a new cabinet.

Egypt's cabinet officially resigned during a meeting following Mubarak's call for them to step down, Nile television station reported.

Tens of thousands of Egyptians defied a curfew and remained on the streets of downtown Cairo on Saturday, demanding the ouster of Mubarak.

As the protests across Egypt entered a fifth day, the military extended a curfew in Cairo, Alexandria and Suez from 4:00 p.m. local time (1400 GMT) to 8:00 a.m. local time (0600 GMT) the following day.

However, the overnight curfew in Cairo was being ignored by angry protesters who flooded the streets of the sprawling city of 18 million and chanted "Down, down, Mubarak," and "Don't believe Mubarak" in defiance of the president's promised reforms.

At least 50,000 protesters gathered in the downtown area near the main Tahrir Square, and some 1,000 of them tried to storm the Interior Ministry, Al Jazeera television reported.

The TV station also reported that police opened fire and killed at least three protesters. No immediate confirmation or further details were available.