MADRID, Spain — A ball of fire erupts from a train car, smothering commuters with smoke, littering the platform with bodies and staining it with blood in a chilling security-camera videotape of the March 11 train bombings broadcast Tuesday by a Spanish station.

The video, taken at Madrid's Atocha station and aired by Telecinco, is believed to be the first public broadcast of images from the bombings that killed 191 people. Telecinco also broadcast video showing an armed, masked Islamic militant claiming responsibility for the attacks on behalf of al-Qaida. The video was found near a mosque in the days after the attacks.

Also Tuesday, the interior minister said a radical Muslim cell broken up this week by police had been plotting to bomb the National Court, a hub of Spain's investigations of Islamic terrorism.

"This was an operation against radical Muslims. They were planning to commit terrorist attacks,'' Interior Minister Jose Antonio Alonso told reporters at Parliament.

The video of the March 11 attacks begins after one bomb has already exploded, with dazed commuters milling about on a smoke-shrouded platform. The time on the tape says 7:38 a.m.

Then, smoke flows toward the camera and people on the platform are knocked over -- apparently by another blast.

About five seconds later, a ball of orange flames erupts from a stopped train, filling the screen. The tape includes no sound, just images.

The video appeared to have been taken from atop an escalator, looking down onto the platform.

Four minutes later, bodies are seen strewn on the platform amid pools of blood. Police and emergency medical staffers attend to them.

After another five minutes, police and crews are seen screaming for people to evacuate the station and themselves are seen running toward the escalator in fear of another explosion. Telecinco said this warning turned out to be a false alarm.

Telecinco also broadcast two other pieces of March 11 video that had not been broadcast publicly, although their existence was known.

One shows a gun-carrying, masked militant claiming responsibility for the attacks on behalf of al-Qaida. The video was found near a mosque on the eve of Spain's March 14 general election.

"We claim responsibility for the Madrid attacks, 2½ years after the blessed conquests of New York and Washington,'' the Arabic-speaking man said, according to Telecinco's translation. He was referring to the Sept. 11 attacks.

In the other video, made March 27, three hooded men wearing belts loaded with dynamite cartridges threaten more attacks against Spain unless it withdraws its troops from Afghanistan.

Those three are believed to have been ringleaders of the March 11 bombing cell and among seven suspects who blew themselves up in an apartment outside Madrid on April 3 as police prepared to storm it.

The original video was found among the rubble of the apartment. The government had said it was badly damaged but it had been reconstructed.

In the seven months since the bombings, Spain has struggled to clamp down on terrorism.

Seven suspects were arrested Monday in Madrid and southern Spain. An eighth was detained Tuesday in Pamplona, the interior minister said. The alleged leader of the cell, Emirates-born Mohamed Achraf, was arrested recently in Switzerland on a request from Spain, a Spanish police official close to the investigation said.

The newspaper El Pais quoted police sources as saying the alleged plot against the court was in the preliminary stages as there was no evidence the suspects had obtained explosives.

Another newspaper, El Mundo, reported that the plan involved detonating a truck loaded with 500 kilograms of explosives outside the courthouse, located on a busy avenue in downtown Madrid.