Algerian police have beaten back around 2000 demonstrators who tried to rally in central Algiers as aftershocks from the Egyptian revolution rumbled throughout the Middle East.

Demonstrations in Algiers quickly turned to running clashes with police who had been ordered by the Government of President Abdelaziz Bouteflika to enforce a protest ban.

Police took up positions throughout the centre of the city hours after the tumultuous scenes in Cairo, which are likely to have significant ramifications across the region.

Even before Egypt's Hosni Mubarak had stepped down, the 12-year regime of Bouteflika had been considered to be under most threat from the popular uprisings now galvanising the Arab states.

Wedged alongside Tunisia, where President Zine al-Abidine Ben Ali was ousted 30 days ago, and near Egypt, which fell on Saturday, the unstable nation has many of the characteristics of both - a disenfranchised youth and rising prices of basic goods, such as sugar and cooking oil.

It also shares a large, pervasive security presence, authoritarian rule and a sense that citizens are not benefiting from its wealth and resources.

Protesters briefly broke a cordon and officials say that 400 were arrested by police - who vastly outnumbered them. Most were then released.

The demonstrations were organised, as they were in Yemen, nearly 6400km away, where 5000 people, mainly youths, rallied in the capital of Sana'a to call for Egypt-style reform.

In Sana'a, President Ali Abdullah Saleh, who took office around the same time as Mubarak and has enjoyed largely unchecked power since, called an emergency meeting of security chiefs and senior ministers hours after the Egyptian leader left Cairo.

Saleh has allowed demonstrations to take place for the past four weeks and has said he would not stand again as President when his term expires in 2013.

Protesters in Sana'a and the coastal city of Aden railed against food prices and poor services.

In Jordan, King Abdullah is yet to form a new government after sacking the Prime Minister and his ministers late last month - a move widely believed to have been inspired by the risk that the revolts may soon be felt there. Weekly demonstrations against prices and services have taken place since December - before the Tunisian uprising - and have focused on similar themes of disenfranchisement.

"Any type of reform will help Jordan not reach the levels of Egypt," said the secretary-general of the Islamic Action Front (Muslim Brotherhood), Zaki bin Irsheid.

"But what happened in Tunis and then Egypt has surprised everyone. No one expected that."

Meanwhile, Syria took the surprise step of unblocking the social media sites Facebook, Twitter, Myspace and YouTube.

The effects of the revolution have also been felt in Iraq, where the Prime Minister, Nouri al-Maliki, has said he will not stand for a third term.

Maliki has ordered three mega-generators to be installed in Baghdad to deal with electricity shortages. "He is terrified about electricity," said one senior Iraqi official. "He is convinced that with the zeal alive in the region now, it will bring his Government down if he doesn't fix it."