I managed to escape. I'm home now. Will file a report shortly.

UPDATE: Here's the report...

Police cracked down today on Kefaya's demo against Mubarak's dictatorial constitutional amendments, arresting more than 20 demonstrators.

Downtown once again (and again and again) has come under occupation since the morning by Mubarak's Central Security Forces troops, plainclothes State Security agents, and battalions of plainclothes thugs which the interior ministry uses to "keep law and order."

As groups started to assemble in Tahrir Sq, police agents moved immediately to encircle them, and pushing them away, trying to convince the protesters to move to the Press Syndicate.

Some, including myself, saw it was pointless to stay in Tahrir with the overwhelming security presence, so we started moving in a group towards Talaat Harb Sq., where we heard security wasn't as heavily present.

We moved slowly in Talaat Harb Street, of course being pushed by security, followed by a battalion of plainclothes thugs and security agents.

But then we stopped, as we received news that GemyHood and Asad were kidnapped by State Security in Tahrir Sq.

[Above: Previous photo I took of detained bloggers Mohamed Gamal and Omar el-Hadi]

Few minutes later, we heard strong chants coming from behind, at the beginning of Talaat Harb St. "Down! Down with Hosni Mubarak!" The march went on for five minutes, before security stepped in and kidnapped Malek Mustafa. CSF forces were mobilized also, and we found ourselves encircled by plainclothes thugs and CSF soldiers. Among those encircled were local and foreign reporters and photographers. Security agents assaulted and confiscated the cameras of Tara Tadross of Reuters and Alexandra Sandels of the Daily Star Egypt. The latter's camera was returned to her without the memory card that had the pix of the assaults.

There was a horrible pushing match back and forth, as they encircled us. One of the plainclothes thugs kicked blogger Salma Said in her stomach. Other activists and reporters were also kicked, punched. Those who have been arrested are more than 20, including: Malek Mustafa (blogger), Adham el-Safty (leftist activist), Omar el-Hadi (blogger), Mohamed Gamal (blogger), Ahmad Droubi (leftist activist), Kareem el-Sha'er (blogger), Omar Mustafa (blogger), Mohamed Awwad (Karama Party activist), Mohamed Abdel Qader, Medhat Shaker, Mohssen Hashem and journalist Jano Charbel.

I managed to escape around 6:35pm, and ran home to post the report. But the Sandmonkey called in to say there were 200 demonstrators under CSF troops siege in front of the Press Syndicate, chanting against Mubarak.

UPDATE: Nasser Nouri managed to photograph the police kidnapping Blogger Malek...

UPDATE: Nasser Nouri has more photos of arrests and scuffles. Click on the pic below to watch a slide show...

UPDATE: I uploaded some photos of the Kefaya march in Tala'at Harb St., moments before the police cracked down on it, kidnapping activists. Click on the photo below to watch a slide show...

UPDATE: There are now demonstrators in el-Ghad Party HQ, overlooking Talaat Harb, who are now under security siege. Plainclothes thugs and CSF troops have blocked the building entrance. There are unconfirmed reports that activists were assaulted and beaten up by the police inside the building, and that activist Ahmad Abdel Gawwad was snatched.

UPDATE: Here's a report by Aziz...

Egypt police break up referendum protest
By Aziz El-Kaissouni
CAIRO, March 25 (Reuters) - Egyptian security forces broke up an opposition protest in Cairo on Sunday, on the eve of a referendum on constitutional changes which opponents fear will strengthen the ruling party's grip on power.
Hundreds of riot police and plainclothes security men were deployed to head off protests against amendments, which rights groups and opposition activists say are a step backward for freedom and democracy.
The government says the amendments are necessary to avert sectarianism and terrorism.
The proposals, if adopted, would allow President Hosni Mubarak to dissolve parliament unilaterally and would weaken judicial oversight of elections, which have been marred by complaints of widespread irregularities.
An anti-terrorism clause would also give the police sweeping powers of arrest and surveillance. In addition the amendments will ban parties based on religion.
"These constitutional amendments are a historical step ... They open new doors for democracy," Mubarak said in a statement carried by state news agency MENA. He added the amendments would also ensure stability in Egypt.
About 19 people were arrested during the protests, security sources said.
"Based on these amendments, unless God shows mercy on us, the future for this country is dark," Muslim Brotherhood leader Mohamed Mahdi Akef told Reuters in an interview. The Brotherhood is the country's largest opposition force, holding a fifth of the seats in parliament.
The government's secular and Islamist opponents say the vote will be rigged.
"It's 100 percent rigged," said Akef. "Watch the balloting stations tomorrow. It'll succeed. (Egypt) has armies of civil servants and factory workers (to vote in favour)."
The Brotherhood, which sees the bar on political activity based on religion as being directed at them, plans to boycott the referendum, along with other opposition groups.
Dozens of opposition activists who turned out to protest the amendments on Sunday evening were blocked by police, who beat protesters with their fists and dragged some off into waiting police trucks in a central Cairo square, a Reuters witness said.
Security officers also shoved several journalists covering the protest and briefly confiscated the camera of a Reuters photographer. They returned the camera after removing the images.
The anti-government Kefaya protest movement has called on Egyptians to dress in black and raise banners of mourning on Monday, and asked activists to hold peaceful protests and strikes across the country.
U.S. Secretary of State Condoleezza Rice, visiting Egypt, voiced concerns over the amendments during talks with Mubarak but said political change would have "ups and downs" and said she would not tell Egypt how to proceed with reforms.

UPDATE: Here's a photo, taken by J Perkins, of the police nabbing a protester...

UPDATE: Here's a video clip I took today of Kefaya's march in Tala'at Harb St., moments before police cracked down, kidnapping Malek Mustafa, followed by others. In the video, you could hear the activists chanting against Mubarak: "We do not want constitutional amendments! We want you to leave and disappear!"

UPDATE: Al-Masry Al-Youm's Amr Abdallah was assaulted today also by the security, who took his camera, deleted the pics on the memory card, and returned it to him. Amr, however, managed to take some photos of the arrests, scuffles, and the demonstration in front of the Press Syndicate. Click on the photo he took below to go to his flickr account...

UPDATE: One of the prison trucks carrying 20 detainees including Malek Mustafa, Omar el-Hadi, Mohamed Gamal, is on its way to Bassateen Police Station, according to lawyer Ahmad Helmi. The chief of investigations at that police station is Major Mohamed el-Sharqawi, who's involved in previous torture case in Helwan before he was transfered to the Bassateen Police Station.

UPDATE: Journalist Jano Charbel has been released. I've just spoken to him now over the phone.

UPDATE: I've just spoken with Chaymaa Hassabu who's been part of the group of activists trailing the prison truck loaded with the detainees. She said they followed the truck till it went inside CSF camp in Tora, and that's when a State Security agent led a team of thugs, encircled the activists' car, and confiscated her driving and car licenses, saying the car was stolen! The police kept the activists under siege for 20 mins, and then returned the papers to them, after stalling them so as not to know where the detainees will be shipped at. It's confirmed now they have been taken to Bassateen Police Station.

WE NEED LAWYERS TO HURRY UP THERE AS SOON AS POSSIBLE! Groups of activists are now on their way heading to assemble in front of the police station.

UPDATE: Lawers said the prisoners' truck was moved from Bassateen Police Station, to the Tora Khayyalla camp, and they were prevented from following the prison truck by security. So we don't know where the Prison truck that has Malek and a group of detainees. The other car that includes Ahmad Droubi, Adham el-Safti, Omar Mustafa, Ahmad Samir, Khaled Mustafa, Sherif Ragab, Mohamed Abdel Qader, Kareem el-Sha'er, is heading towards el-Tagammu el-Khames, east of the capital.

UPDATE: Released journalist Jano Charbel confirmed Ahmad Droubi was pepper-sprayed as he was detained. Jano was in the same truck with Droubi and the others. The police stole LE100 from Jano, and confiscated both his camera and phone memory cards. He said the truck took him and the detainees to some garbage dump near Moqattam, where Jano was released. The rest, the lawyers say, have been taken to el-Tagammu Khames.

UPDATE: Activist Bassem Khalifa confirmed he and four women protestors were pepper-sprayed when they were encircled in Tala'at Harb by the CSF and plainclothes police thugs.

UPDATE: It's 12:20am... An activist called to say Kefaya blogger Malek Mustafa has been releaed. Police dropped him somewhere near the Cairo International Air Port. We do not have more details about the detainees who were with him.

UPDATE: It's 12:40am... Lawyer Ziyad el-Aleemi says detainee Medhat Shaker was released along with Malek. The truck carrying the other group of detainees including Droubi is right now parked in front of the Chouifat International School in el-Tagammu el-Khames.

UPDATE: It's 1:10am now... Malek called. He's alright now. They beat him in the street before they dragged him into the prison truck, that kept cruising. He says there was only him and Medhat in the car, and that they were not beaten up any more once they were in custody. Medhat was dropped by the police in front of the Cairo International Conference Center, while Malek said he was released around 12:15am when police suddenly told him to get off the car close to the Cairo Airport.

UPDATE: It's 1:20am now... A blogger called from the Press Syndicate saying he spotted the police general who's been supervising today's assaults against protesters, leaving in a private white Peugeot, with Cairo license plates # 63835

UPDATE: It's 1:40am... The blogger from the Press Syndicate called in again to say he spotted the police general who supervised the thugs assaults on protesters back in 7 September 2005 demos, leaving the scene today in a private white Peugeot 504, with car license plates #358926

UPDATE: It's 2:40am... We've lost trail of the Prison Truck that had the eight detainees in el-Tagammu el-Khames. Now we have two prison trucks loaded with detainees some-bloody-where in Cairo that we just do not know. There are strong concerns for the safety of detained activist and biologist Ahmad Droubi who is a diabetic. Medical negligence almost killed Droubi last year when he was locked up in Tora during Mubarak's crackdown on the pro-judicial independence movement. We hold Mubarak's Interior Ministry responsible for Droubi's health and safety while they keep him in that cruising prison truck of theirs.

[Above: Photo I took of Droubi last February]