Gunmen wielding grenades, AK-47 rifles and a human bomb stormed the Indian Parliament on Thursday, killing seven people before being killed themselves.

There was no immediate claim of responsibility, though Home Minister Kal L. Advani declared "terrorists and their sponsors" were to blame.

Security forces killed five attackers during a 90-minute gunbattle. Another attacker may have escaped.

Prime Minister Atal Bihari Vajpayee, who reportedly was just leaving the Parliament building when the attack took place, delivered a live television address two hours after the gunbattle ended to reassure the nation that the government had things under control.

"This was an attack not just on Parliament house, but a warning to the entire country. We accept the challenge. We will foil every attempt of the terrorists," Vajpayee said.

In addition to the 12 dead, the attack left 18 people injured, six critically, Advani said.

No lawmakers or Cabinet officials were among the casualties. Parliament had just adjourned at the time of the attack, and most officials were still inside the building.

Advani warned last week that a Bombay man was arrested Oct. 2 and told police that he had trained under Usama bin Laden's Al Qaeda terrorism network, blamed for the Sept. 11 attacks on the United States. The suspect told police that Al Qaeda had planned to attack Britain, Australia and the Indian Parliament, according to the home minister.

In the dramatic assault, the car sped through a gate and one militant jumped out, blowing himself up, while the others opened fire on police and security guards, according to state-run Doordarshan television.

Parliament officials said that four police officers, one unarmed paramilitary guard, a woman paramilitary constable and a gardener were killed in the attack.

Advani said five terrorists were killed and that another attacker may have been involved.

"The situation is not clear," he said.

Earlier, Pramod Mahajan, India's parliamentary affairs minister, said that six terrorists had been killed in the 90-minute battle, called the worst breach of government security in this nation since the assassination of Prime Minister Indira Gandhi in 1984.

Police found explosives in the militants' car and in the turquoise knapsacks that the young, clean-shaven, black-haired gunmen had slung over their backs as they raced up the steps of the Parliament building, firing their assaults rifles with one hand.

After three hours, when the Parliament members had been evacuated, police found and set off a remaining bomb in a controlled explosion. Police said several grenades were also defused.

Journalists who were inside the building said there were bullet holes on the doorways. Bodies were lying on the lawns and sidewalks near the gate as ambulances rushed to the scene. A television cameraman was also shot, and private Star News said police were firing indiscriminately, including at journalists.

"Someone started shouting, 'terrorists, terrorists,'" said lawmaker Khara Bela Swain. "I couldn't understand anything. There was chaos.''

Videotape obtained by Associated Press Television News showed the body of the suicide bomber, without arms or legs, lying on a sunlit walkway in front of the sandstone building.

The tape showed his comrades, dressed in green sweaters, racing toward the building, then back again behind a wall in the surrounding park, firing their rifles as they where shot by police.

The gunmen had driven through one of the Parliament complex's 12 gates in a white, Indian-made Ambassador car, of the kind used by government officials, said Doordarshan. A siren on the car was wailing and official stickers from Parliament and the Home Ministry were affixed to the windshield, the report said.

"After three or four minutes of firing they started throwing grenades," and at least four exploded, Swain added. "I started to run to save my life."

Hundreds of rounds were fired as police hid behind cars, trees and the corners of the building. The dramatic standoff was broadcast live on most television stations.

The U.S. Embassy condemned the attack as an "outrageous act of terrorism." Foreign Secretary Jack Straw of former colonial ruler Britain said the "brutal terrorist attack" was an assault on "the heart of India's democracy."

"Today's attack is the most serious breach of top security in Delhi since Indira Gandhi's assassination in 1984," said political analyst Mahesh Rangarajan. Gandhi was killed by her Sikh bodyguards in revenge for sending her troops into the Sikhs' most sacred shrine, the Golden Temple in Amritsar.

Advani said that Thursday's attack was similar to one on the state assembly in Srinagar, the summer capital of the northern Jammu-Kashmir state, where Islamic militants for 12 years have been fighting for independence or a merger with Pakistan.

Forty were killed in the Oct. 1 attack when a car was rammed into the legislative building's gate, a suicide bomber blew himself up with the vehicle and several militants engaged in a gunbattle with police inside.

Pakistan's foreign ministry spokesman, Aziz Ahmed Khan, said Islamabad was shocked by Thursday's attack and strongly condemned it.

When asked who might have been responsible, Advani said: "It may be one of the organizations which have been active in the country. Ever since this practice of suicide terrorism has been developed, anything can be attacked."

Advani said he wasn't only referring to the Oct. 1 attack in Srinagar, but the Sept. 11 terrorist attacks on the United States.

Apart from Sikhs and Kashmiris, India has had to grapple with some 30 tribal groups seeking independence or greater autonomy in the seven northeastern states wedged between Bangladesh and Myanmar.

The Associated Press contributed to this report.