Suicide bombers crashed two vehicles loaded with more than a ton of explosives into the courtyard of the Russian government headquarters in the Chechen capital of Grozny today, killing at least 46 people inside and wounding at least 76 others.

It was the deadliest attack yet on Russia's hard-pressed civilian government in Chechnya and a fresh indication that suicide tactics are gaining popularity among those who want to break Russia's shaky hold on its separatist southern republic.

Television footage showed stunned workers, their faces covered with blood, being helped out of the gutted building, past bodies laid out on the snow-covered ground. A group of men were shown digging in the rubble with their bare hands, apparently trying to rescue buried colleagues, while nearby a wailing woman beat her thighs.

"It was like an earthquake," said Shamsail Saraliyev, the Chechen government's press secretary, his forehead streaked with blood. "Everything was covered in smoke. The building collapsed and there were people in there."

Soldiers at the scene told reporters that a truck and a jeep rammed through the building's heavily guarded perimeter this afternoon and exploded less than 35 feet from the entrance. The blast reduced the four-story headquarters -- often cited by Russian officials since it opened 21 months ago as a symbol of growing peace in Chechnya -- to a windowless shell indistinguishable from the rest of the charred structures in the ruined capital of roughly 500,000.

The attack also threw President Vladimir Putin back on the defensive after what seemed like a semi-victory over Chechen militants two months ago, when Russian forces managed to free hundreds of hostages held captive in a Moscow theater. Most of the more than 800 hostages escaped safely, but the opiate-like gas used to subdue the guerrillas killed 129, as well as more than 40 rebels. Today's attack showed that the Kremlin's representatives in Chechnya are under siege and Putin is nowhere close to resolving the long-running conflict.

"The rebels have proved in their own way that they can do anything they want," said Alexei Malashenko, an expert on Chechnya with the Carnegie Endowment's Moscow Center. "It's very bad for Putin because he had hoped to say something about triumph and now he has this."

The event is likely to make it even more difficult for the Kremlin to recruit the Chechen workers it needs to keep order, run schools and deliver pensions in the territory, located in the Caucasus Mountains between the Black and Caspian seas. Scores of Chechens who work for the Moscow-led government have been assassinated by rebels since Russia launched a new offensive against the rebels three years ago. Russian forces withdrew from Chechnya in 1996 after three years of inconclusive fighting.

Russia's national television news networks, most of which are financially influenced or controlled by the state, emphasized the organization of rescue efforts and shied away from extensive footage of the carnage. But the extent of the disaster was clear even from the limited video shown.

The government's four-story headquarters was one of the few places in Grozny that Kremlin officials considered secure enough for foreign journalists to visit. It is surrounded by a concrete barrier and three heavily guarded checkpoints. Roughly 200 people -- many of them Chechens -- work in the building. Some also live on the compound because it was considered more secure than the rest of the city.

About 2:30 p.m., soldiers told reporters, a Kamaz heavy truck rammed through the gates, followed by a jeep. TVS, an independent national television network, reported that the racing jeep exploded after soldiers opened fire. The truck exploded 30 seconds later with a force equivalent to at least one ton of TNT, officials estimated. The blast blew out the windows of buildings one-third of a mile away.

A TVS reporter on the scene said he saw people without limbs half-buried under concrete slabs. His station's footage showed one woman stagger out of the building gasping, "I cannot bear it." A rescue worker ran up to her and demanded: "Where is your daughter?"

The search for survivors continued well past nightfall, with three cranes lifting giant beams out of the rubble. "We don't know so far how many people are still under the wreckage," said Vladimir Kravchenko, the top Russian prosecutor in Chechnya.

The injured overwhelmed Grozny's two working hospitals. Television footage showed medical personnel running through corridors packed with the wounded. ORT, a state-owned television network, reported that power was out at the hospitals and surgeons were forced to operate by candlelight. Emergency officials said the injured would be airlifted to military hospitals.

Russia's top civilian leaders in Chechnya escaped the blast. Akhmad Kadryov, head of the government, was in Moscow. Chechnya's prime minister was also traveling outside Grozny. Rudnik Dudayev, head of the Chechen Security Council, was hospitalized with a head injury.

Russian media at first reported that law-enforcement authorities in Moscow had been put on high alert and security was beefed up throughout the capital. But a top police official later denied that, saying more officers were on the streets and in the subways because of the approach of New Year, Russia's biggest holiday.

This latest attack, along with the seizure of the Moscow theater, shows militants are relying on ever more shocking acts of terrorism, analysts said. That further diminishes any chance of a peaceful solution to the Chechen conflict, they said, because Putin has vowed never to negotiate with terrorists.

Putin late tonight sent a telegram to Kadryov, the head of the Chechen government, that read in part: "All Russia is mourning those killed in the terrorist act. People who prepared and carried out this inhumane act are waging a war against their own people."

No one claimed responsibility. In a statement posted on a rebel Web site, Akhmed Zakayev, an envoy for Chechnya's separatist government-in-exile, said the attack "may be regarded as a terrorist act." But he added, "there may be others who will assess today's event as a successful retribution act from Chechens." Moscow is currently trying to have Zakayev extradited from England to face charges of armed insurrection and other alleged crimes.

Boris Nemtsov, leader of the progressive Union of Right Forces party, argued today that negotiations remain the only solution to the conflict. "This horrible terrorist act shows that Chechnya is very far from peace and one should find the courage to admit it," Nemtsov said.

The latest chapter of the conflict began in late 1999, after Chechen guerrillas mounted an incursion into neighboring Dagestan. The Kremlin also blamed militants for explosions of apartment buildings in Moscow and elsewhere in Russia during the fall of 1999 that killed hundreds of civilians. Since then, roughly 80,000 Russian troops have been stationed in Chechnya to fight guerrillas, whose numbers are estimated at a few thousand.

A wounded woman is helped from government headquarters in Grozny after suicide bombers exploded two vehicles in the courtyard.TV footage shows the Russian government headquarters after suicide bombers crashed two vehicles loaded with more than a ton of explosives into the grounds of the building, which was opened as a symbol of growing peace.