Egyptian security forces are standing ready to clamp down heavily on protesters, as the riots that have gripped the Egyptian capital enter their third day.

Anti-riot vans patrol Cairo’s boulevards early Thursday morning. The large armored trucks used by police to take away arrested protesters stand parked near flashpoints in the city, and amin dowla (plain clothes officers) from the state security service are everywhere.

On Wednesday over 2,000 people clashed with anti-riot police on the capital’s thoroughfare, a continuation of their call to bring an end to Egyptian President Hosni Mubarak’s 30 year rule.

At least three protesters and one policeman have died in the violence thus far. Police have beaten protesters and journalists alike and dispersed the crowds with water cannons, tear gas and rubber bullets. Over 860 protesters have been arrested since the riots began Tuesday.

The mood in the city center’s Tehrir square, where some of the most violent clashes have taken place, remains extremely tense early Thursday. Rows of anti-riot police line the junctions to the square, equipped and standing in charge formation. Security officials ward off bystanders in the area. A police man swings his baton menacingly, pinging it against the lamp post as I walk by.

“You can’t stay here. Move,” a man warns me as I pass Pizza Hut on the main square. The walkie-talkie under his shirt crackles, giving him and the group he is with away as undercover security.

The men are jumpy, any innocent question is met with the accusation; ‘sahafi’? Journalists are not welcome, and working openly in public is dangerous. The Guardian’s Egypt correspondent, Jack Shenker, was arrested during the riots and was only beaten more upon the revelation that he is a journalist.

The plain clothes security are dotted on street corners, muttering in low voices, donning leather jackets, watching passers by. They are conspicuous in their lack of concern for being in a group, despite Egypt’s Interior Ministry ban on public unauthorized assemblies.

Some 20,000 to 30,000 police have been deployed in the central areas of Cairo. But despite the police numbers, in the early hours of Thursday morning smaller groups of protesters continue to assemble.

Even those not participating in the riots have spoken against Mubarak and his strong handed rule, emboldened by the Tunisian popular deposition of dictator Zine El Abidine Ben Ali; ‘Everybody hates Mubarak,’ says one citizen. “He has been in power here for 30 years! In other countries leaders are only in power for two or three years. Why can’t he and his son Gamal just go?”

For others the focus remains on trying to maintain business as usual. Along the bank of the Nile river, a concierge at the Intercontinental hotel, located meters from Tehrer square smiles widely when asked if the area is dangerous; painting a veneer of calm he says, ‘there is no problem here’.

Despite police measures to put an end to the riots, the protesters have thus far managed to stage the biggest anti-government rallies of Mubarak’s 30 years in power.