At least 46 people were killed and over 76 injured on Friday when two vehicles laden with explosives rammed into the high-security government headquarters in Chechen capital Grozny and practically destroyed the building.

A truck and a jeep at full speed rammed into the gates of the government building complex surrounded by a three-metre high concrete fence at 1420 hours (local time).

One of the suicide bombers in the jeep set off explosives near the telecommunication centre while the driver of the truck set it off near the main building, Chechnya acting prosecutor Vladimir Kravchenko told a television channel.

TV channels showed scores of men and women employees running helter-skelter around the compound with bleeding faces. Dozens of parked cars were flattened and charred by the two explosions, killing or wounding their occupants.

Five people have been rescued from the wrecked building so far, Interfax news agency quoted a Russian emergencies ministry official as saying.

According to Grozny Deputy Mayor Supyan Makhachev, the toll could rise as there could be people buried under the debris of the ground and first floors of the four-storey building complex.

Scores of government employees had converged on the worst-hit part of the ground floor, housing the treasury, to receive their pay ahead of the New Year holidays.

Pro-Moscow Chechnya administration chief Ahmad Kadyrov, who was in Moscow on a business trip, has accused Chechen separatist leader Aslan Maskhadov and rebel warlord Shamil Basayev of unleashing terror in Chechnya to scuttle a constitutional referendum scheduled for next March.

Moscow and Grozny had also held Maskhadov and Basayev responsible for the October theatre siege in the Russian capital in which 49 suicide attackers and 129 hostages were killed in the course of a security operation to end the siege.

This is the second terrorist attack on the pro-Moscow administration of the breakaway republic this year.

On October 10, 20 top police officials were killed in a bomb blast inside a police station in Grozny.

President Vladimir Putin, who was immediately informed of Friday's terror attack, has ordered a security alert throughout the country ahead of the week-long New Year holidays.

In Moscow, all policemen have been told to report to duty and their leave has been cancelled till further notice.