MOSCOW, Dec. 27 — Suicide bombers plowed two explosive-laden vehicles through a military perimeter today and blew up the headquarters of Chechnya´s pro-Russian government in Grozny, killing at least 46 people and wounding scores more in two terrific blasts.

It was the deadliest bombing inside Chechnya in more than three years of war, and it sent yet another powerful signal that militants seeking to split the semiautonomous Chechen region from Russia are far from being subdued.

The last signal came barely two months ago, when Chechen separatists took control of a Moscow theater and terrorized hundreds of hostages for several days. The government raid that ended that crisis resulted in the deaths of nearly 130 civilians.

The regional government office in Grozny, the Chechen capital — which was opened to great fanfare barely 20 months ago as a beacon of political stability — was among the most protected buildings in the area.

Russian television showed images today of civilians and soldiers, many soaked in blood, stumbling or being carried from the wreckage of the four-story concrete building. A huge crater near the entrance, more than a dozen feet deep, marked the site of the explosions.

Tonight Russia´s Emergencies Ministry put the death toll at 46. Another 70 people were reported to have been taken to hospitals, at least 20 of them critically injured. But an Emergencies Ministry official said the number of injured could reach 200, because the blast had destroyed a nearby two-story building, containing a canteen and government offices, as well as the main building.

Wounded government workers were still being removed from the canteen and other areas tonight, and three cranes were lifting concrete rubble in search of victims.

"We do not know so far how many people are still under the wreckage," Chechnya´s acting prosecutor, Vladimir Kravchenko, told the Interfax news service.

The region´s first deputy finance minister, Stanislav Tereshchuk, said the second building was crowded with ministry workers who had been reconciling the Chechen government´s books on one of the last working days before New Year´s Day, Russia´s biggest holiday.

"I didn´t hear the second blast," Mr. Tereshchuk, clearly dazed, said in a television interview. "The first one was too strong. Our information and technical section room caved in. I am sure one of my people was there. We had just hired him."

The head of Chechnya´s civil administration, Akhmad Kadyrov, and the new prime minister, Mikhail Babich, were away from the building when the blast occurred.

In Grozny, a rubble-strewn wasteland since Russian jets destroyed it in late 1999, Hospital No. 9, the main hospital treating victims of the blast, was without power. Interfax reported that doctors were working by candlelight and flashlight.

President Vladimir V. Putin met tonight with the head of the Federal Security Service, the domestic successor to the K.G.B., for a report on the bombing.

The bombers, traveling in a large truck and an off-road vehicle, struck shortly before 2:30 p.m., barreling through the last gate of a heavily fortified perimeter surrounding the government headquarters. The blasts devastated the main building — blowing out all of its windows and extensively damaging its front — and largely destroyed the adjacent canteen.

The offices of the regional prosecutor and the Federal Security Service were also damaged.

It is not clear how the bombers gained access to the government complex, which was deliberately set on a barren stretch of land and divided into sectors walled off by concrete fences.

The TVS television network reported tonight that drivers of heavy trucks required a special pass to enter central Grozny. The drivers would have had to pass through two checkpoints at the government compound before reaching the last gate, which raised the prospect that a security breakdown was responsible for the disaster.

The government-run ORT television reported tonight that the heavy truck bore military license plates.

Mr. Kadyrov told Interfax that officials would search for security lapses that might have permitted the bombing, but he despaired of its doing much good. "We have done this so many times, and what´s the use?" he said. "Terrorists still rule in Grozny."

Russian troops sealed off all roads around Grozny and mounted a search for organizers of the attack.

"This is the latest monstrous atrocity by the terrorists, those very same people who staged the explosions in Moscow, Volgodonsk, Buinaksk and Grozny," Mr. Putin´s human rights representative in Chechnya, Abdul-Khakim Sultygov, said tonight on ORT. "These are people who have openly declared war on their own people. They are, of course, in their death throes."

Mr. Sultygov was referring to bombings in late 1999 — mostly unsolved but ascribed to Chechen militants — which heavily influenced Mr. Putin´s decision to send the Russian Army into Chechnya for the second time in five years.

Russia effectively lost the first war, giving Chechnya de facto independence. Moscow has claimed victory in the second, saying it has reduced the guerrillas to a handful of scattered and hunted bands. The Kremlin recently released a draft of a new Chechen constitution as a prelude to a spring referendum on forming a new government.

But Russia´s military grip on Chechnya has remained shaky at best. Russian soldiers die weekly in ambushes, and Chechen militants effectively have the run of Grozny at night. The blast today, the fourth major strike against Russia´s presence in Chechnya in five months, suggests that militants are increasingly resorting to headline-grabbing acts of violence to press their cause.

More than 40 Chechen militants seized a theater in the heart of Moscow in October, provoking a costly rescue attempt by Russian forces that left the militants as well as nearly 130 theatergoers and performers dead.

Another 121 people died in August after guerrillas shot down an overloaded military transport helicopter over the main Russian military base outside Grozny. Twenty-two died in October when a bomb destroyed a Grozny police station.

The military warned last month that suicide bombers were planning a series of strikes in Grozny and central Russia, with their principal targets likely to be government buildings, including the one hit today.

Indeed, the same building was bombed in September of last year, less than five months after it opened, when an explosive device left in a women´s restroom went off, killing a cleaning woman. In July investigators found tons of saltpeter and a bomb in a garage about 1,000 feet from the building — enough, police officials said then, to level the complex.

Tonight Mr. Kadyrov, the head of Chechnya´s civil administration, called the latest bombing the work of militants tied to Aslan Maskhadov, a onetime Chechen president who is commander of the Chechen guerrillas, at least in name. A spokesman for Mr. Maskhadov, Akhmed Zakayev, denied that tonight.

Others blamed Islamic extremists, some of them foreigners, who have sought to reinvent Chechnya´s separatist movement as an Islamic revolution.

While suicide bombings have been a hallmark of Islamic extremism elsewhere, one Moscow expert on Russian regional problems and the Russian military, Dmitri Trenin, said labeling those responsible for the explosions might not be so simple. "Islamic extremism is part of it," said Mr. Trenin, a scholar at the Moscow Center of the Carnegie Endowment for International Peace. "Part of it is separatism. It´s a deadly cocktail that you have out there."

He said major acts of sabotage like this might grow more common, in Chechnya and other parts of Russia, because they had proved to be the one means of striking at the Russian presence against which there was little defense.

"Russia, as we have seen, cannot even seal its capital from such acts of terrorism," he said. "On the other hand, these same forces cannot hope to drive Russia out. Unfortunately, I think we are stuck with what we have now." (Copyright 2002 The New York Times Company 12/28/02)