According to BBC, protesters have taken over the centre of the Egyptian capital Cairo on the sixth day of demonstrations against the rule of President Hosni Mubarak. The police, who have been involved in violent clashes with protesters in recent days, have largely disappeared from the streets. There is a heavy military presence in the city, but soldiers are not intervening. The government has announced that al-Jazeera must halt operating in Egypt. The Arabic TV channel, which has been showing blanket coverage of the protests, says it has yet to receive a formal order from the authorities.

Clashes between protesters and the security forces - mostly riot police - are reported to have left at least 100 people dead across Egypt since rallies began on Tuesday. Thousands have been injured as violence has flared in cities including Cairo, Suez and Alexandria.

The BBC's Jeremy Bowen says that although key government buildings are under heavy guard, there appears to be a vacuum of authority in large areas of the city. Throughout the city, armed citizens' groups have formed to respond to the widespread looting and disorder that has accompanied the growing sense of lawlessness. Across Egypt, thousands of prisoners are reported to have escaped from jails after overpowering their guards.

The US government, which previously had advised US citizens against non-essential travel to Egypt, is now advising Americans in Egypt to consider leaving the country as soon as possible. The UK has advised against all but essential travel to Cairo, Alexandria, Luxor and Suez. A number of other European countries have also advised against visiting the country.