The television news crew had been preparing to cover a meeting of the Judges Club called to discuss supervising the coming multi-candidate elections.
Aljazeera correspondent Samir Omar said the police tried to persuade the TV crew not to cover the meeting live. When the journalists refused, the police detained them until the meeting was over, he said.
In that meeting, the Judges Club demanded judicial independence and announced that judges would not participate in the supervision of any future parliamentary or presidential elections unless their demands were fully met.
The group has been urging the government to allow judges to fully monitor presidential elections that for the first time will be open to more than one candidate.
They have also demanded the approval of a law on the independence of judicial authorities.
Mubarak supporters were out in
force too on Friday in Cairo
Soon after the Aljazeera crew were detained, an Arab journalists' group condemned the security authorities' action.
The Arab Committee for the Defence of Journalists in a statement described it as repressive and urged the Egyptian government to recognise growing demands for freedoms.
On Tuesday, Egypt's parliament overwhelmingly passed a constitutional amendment allowing multi-candidate elections and it will be put to a public referendum on 25 May.
However, critics charge that the restrictions are so tight that only members of President Hosni Mubarak's ruling party would be able to run.
Previously, Mubarak was repeatedly re-elected in yes-no referendums in which he was the only candidate.
Also on Friday, supporters and opponents of Mubarak held rival demonstrations, facing off against each other amid a heavy ring of anti-riot police in a downtown Cairo square.
About 500 demonstrators carried banners reading "Yes to Mubarak" and chanted, "Traitors, get out of here!" to the anti-government protesters who had gathered metres (yards) away inside the journalists' union building.
The amendment was passed
on Tuesday amid a walkout
"I came here because I want Mubarak to serve for another term," Qadri Sabah, a food delivery worker who joined the rally also attended by a number of ruling National Democratic Party members, said.
Some threw stones at the union building, where an equal number of demonstrators of the Kifaya, or Enough, movement had gathered, shouting, "Down, down with Hosni Mubarak!"
"Our goal is to express our solidarity with the judges without clashing with the Mubarak supporters," George Ishak, a leading member of Kifaya, said.
Ishak was referring to the judges' meeting that later began under a tent outside the nearby Judges' Club.
Near the pro-Mubarak crowd, another group of about 150 people, mostly lawyers, gathered in support of the judges. "We do not want to put pressure on the judges," activist Hamadi Sabahi said.
"The ones who are pressing them are those poor people standing outside the (union) and shouting for Mubarak in return for money."