Cairo, Egypt (CNN) -- Areas of Cairo might as well be under martial law. This normally chaotic but otherwise peaceful city of 18 million has been wracked by football fever gone mad. The government has deployed thousands of riot police and plain-clothed cops in a part of town normally known for its fancy restaurants and upscale shops.
Thursday night thousands of angry football fans descended on the island of Zamalek, a posh neighbourhood popular with rich Egyptians, diplomats, businessmen and journalists. They were heading to the Algerian Embassy on Hassan Sabri Street.
Wednesday evening the Algerian and Egyptian football teams faced off in Khartoum, Sudan, for a final qualifying match for the 2010 World Cup, aptly described by the Daily Telegraph as the "play off from hell." Algeria won 1-0, earning itself a spot in the 2010 World Cup and sending Egypt home.
Egypt and Algeria came to a standstill Wednesday evening to watch the match, played in Khartoum's Marreekh Stadium. Al-Marreekh is Arabic for the planet Mars, and Mars, of course, was the god of war.
The football rivalry sparked a nasty media war, in which each side accused the other of murdering their respective nationals and trashing property. The Algerian government suddenly slapped the Egyptian telecom giant Orascam with a back-tax bill of nearly $600 million for what Orascam calls "unfounded and unacceptable" claims.
On Friday one Cairo daily ran a banner headline-in red-"TERROR IN SUDAN" featuring large colour photographs of a women with a bandaged head, and a police officer holding a long knife which the caption said had been used by an Algerian football fan against an Egyptian supporter.
YouTube now has plenty of postings in which Egyptians and Algerians curse one another in the most colorful of language.
All of this is fueling anger and resentment.
In Zamalek Thursday evening, the crowd couldn't get through the police blockade, but vented its anger by smashing car and shop windows.
Eyewitnesses say the police initially did nothing to stop them. The assumption is that the authorities wanted the crowd to let off steam, and then go home.
But it was a tactic that didn't work. As word spread around Cairo, more people, mostly young men but a fair number of women as well, made their way to Zamalek. And clearly the police had miscalculated. They were pelted by rocks and bottles, and replied in kind. According to the Interior Ministry, more than 30 policemen were injured.
And to top it all off, the crowd turned over one of the ubiquitous riot police trucks and torched it.
After this night of chaos, the government adopted a policy of zero-tolerance Friday. Thousands of riot police lined the streets of Zamalek. The road leading to the Algerian Embassy was closed to traffic.
As is so often the case when the police are frustrated, they turn on journalists. When CNN Cairo camerawoman Mary Rogers tried to videotape a young woman with an Egyptian flag arguing with a policeman, about half a dozen cops jumped on her, grabbing her camera.
When I protested, and put my hand on the camera, they pounced on me, ripping my shirt open. Two brawny men in civilian clothing grabbed my upper arms and pulled me away. Naturally I protested, which just brought more of them down on me. I now sport two very large bruises on my arms from this encounter with the law.
To cut a long story short, after much screaming and shouting, radio and phone calls, we were told we could go. There was just one problem. The tape was not in the camera anymore. Of course, the police had no idea what had happened to it.
"This is not Egypt! They are not Egyptians," a young man who witnessed our detention told me, pointing up the road to the riot police.
But the underlying problem, perhaps, has nothing to do with football, or Algeria. Rather, there is bedrock of deep resentment among many Egyptians -- poor and well-off alike -- against an ageing, authoritarian regime widely perceived as more concerned with self-preservation and self-enrichment than the general welfare.
Today I overheard one woman -- she described herself as a housewife -- berating a police officer. "We are 80 million people in this country. We have to struggle to get by, and all you police do is beat us."
The predicament of Egypt was eloquently laid out by Egyptian journalist Sara Khorshid, who recently wrote in Cairo's Daily News: "Till this day, Egyptians continue to be stripped of their dignity, standing still vis-a-vis corruption, lawlessness, and unfair distribution of power and wealth between a small rich circle and a disadvantaged majority, whose patience may not be guaranteed for long."
The post-match uproar may pass in a day or two. But it's a stark reminder that Egypt's appearance of calm and stability may be deceiving.