Prominent Egyptian reform campaigner Mohamed ElBaradei said he expected large demonstrations across Egypt on Friday and that the time had come for President Hosni Mubarak to leave power.

'He has served the country for 30 years and it is about time for him to retire,' ElBaradei, a Nobel Peace Prize-winning former head of the UN nuclear watchdog, told Reuters shortly before he was due to leave Vienna for Cairo on Thursday.   

'Tomorrow is going to be, I think, a major demonstration all over Egypt and I will be there with them,' he added, calling for peaceful protests.

Egyptians torched a police post in Suez early on Thursday in response to the killing of three demonstrators earlier in the week, a Reuters witness said. Police fled the post before the protesters burned it using petrol bombs.   

On Wednesday evening, people in Suez had set a government building and another police post on fire and tried to burn down a local office of Egypt's ruling party.   

Those fires were all put out before they engulfed the buildings but dozens more protesters gathered in front of the partially burned police post later on Thursday morning.   

A Twitter entry called for a march at 3 pm (1300 GMT) on Thursday in Giza, an area of Cairo.

The anti-government protests, unprecedented during Mubarak's rule of a state that is a key US ally, have seen police fire rubber bullets and tear gas at demonstrators throwing rocks and petrol bombs.

One policeman has been killed in Cairo in the clashes, which erupted on Tuesday, inspired by a popular revolt in Tunisia.

Thousands of protesters also took to the streets in Yemen on Thursday to demand a change of government there.

Protesters in all three countries complain about surging prices, a lack of jobs and authoritarian rule that has relied on heavy-handed security to keep dissenting voices quiet.   

Al-Arabiya television said on Thursday Egypt's general prosecutor had charged 40 protesters with trying to 'overthrow the regime'. 

A page on Facebook announcing Friday's protest gained 55,000 supporters in less than 24 hours. 'Egypt's Muslims and Christians will go out to fight against corruption, unemployment and oppression and absence of freedom,' wrote an activist on Facebook, which alongside sites like Twitter have been key tools to rally people onto the streets. - Reuters