By Jane Bradley and Shan Ross

But some protesters and police embraced. Many nodded in agreement or said they would join demonstrators. One officer raised his fingers in a “V for a victory” sign. Others shouted words of encouragement and apologies at each other.

The protests were organised on social networking sites such as Facebook and Twitter before internet and phone connections were cut off yesterday afternoon.

Live television footage showed the ruling party headquarters on fire in Cairo and Al Jazeera TV reported military vehicles entered a central square in the capital to cheers from demonstrators.

Arab neighbours watched nervously as the unrest spread to Cyprus last night, where thousands of Turkish Cypriots in the north banged drums and blew vuvuzelas at a rally in Nicosia to voice their disapproval at policies they say are driving young people off the island to look for jobs.

Thousands marched in Jordan demanding that their president stand down.

The unrest was sparked by protests in Tunisia two weeks ago.

The US last night threatened to reduce a $1.5 billion programme of foreign aid to Egypt based on Mr Mubarak’s response to the protests.
“Violence is not the response” to the demands for greater freedoms, said White House spokesman Robert Gibbs.

US Secretary of State Hillary Clinton urged Egypt to rein in its security forces, escalating pressure on an important ally. “We urge the Egyptian authorities to allow peaceful protests and to reverse the unprecedented steps it has taken to cut off communications,” she said, referring to the blocking of internet social networking sites.

“These protests underscore that there are deep grievances within Egyptian society, and the Egyptian government needs to understand that violence will not make these grievances go away.”

Speaking at the World Economic Forum in Davos, Switzerland, Prime Minister David Cameron echoed her calls for restraint. He said: “I don’t think it’s in anyone’s interest that people are being killed on the streets of Egypt as we speak at the moment and so I hope the violence will cease.

“But clearly, when you have people who have grievances and problems that want them responded to, it’s in all our interests that these countries have stronger rule of law, stronger rights, stronger democracy.”

Reports claimed that a large number of police stations in Alexandria had been burned to the ground, while local media reported that protesters had stormed the Egyptian state television building in central Cairo.

Egypt’s national carrier last night said it had suspended its flights from Cairo for 12 hours. The company said its flights from abroad will be able to land, but added departures were cancelled from 9pm Egyptian time.

People flying from Britain to Cairo were warned of changes to flight schedules because of the situation.