By Stephen Mulvey BBC News Online's Europe editor

The devastating bomb attack on the Chechen Government in Grozny proves, once again, that the Chechen war is far from over.

If anything it is cranking up.

It is war of guerrilla raids, rather than battlefield engagements, and the scale of the attacks launched by the rebels is on the rise.

The death toll has been particularly large in two recent attacks:

• In August the rebels killed 116 soldiers in a single missile attack on a Russian helicopter - the largest Russian casualty total since the second Chechen conflict began in 1999.
• In October they took 800 people hostage in a Moscow theatre, of whom 129 died as Russian special forces stormed in to rescue them.

Fewer people died in the latest attack on Grozny, but the heart of the pro-Russian administration in Chechnya has been blown apart.

Symbolically, it is a tremendous blow to Russian prestige.

No killer blow

The might of the Russian military has once again been made to look weak by a group of determined rebels, some of them prepared to die for their cause.

Pro-Moscow governments will always be a target

"How long," Russians will be asking, "can this continue?"

The answer, given the current record of the Russian security services is: "Indefinitely".

In the first Chechen war, from 1994 to 1996, the Russian army suffered the ultimate humiliation - it was driven out of the breakaway republic in ignominious defeat.

In the three years since the second war began in 1999 the security forces have dug themselves in and forced the rebels underground, but at huge cost.

The Russian death toll has risen relentlessly, while the punitive raids by Russian forces on Chechen civilians have done immense damage to the country's international reputation.

Meanwhile none of the competing agencies fighting Moscow's hand in the republic - the regular army, the interior ministry, and the Federal Security Services - has shown itself capable of delivering a killer blow to the rebels.

Hard line

The impression of disarray has only been heightened by the sacking of two top generals in the last week, including the head of army operations, Gennady Troshev.

Russian soldiers can never completely relax

But Russia has no real alternative at the moment to a military solution.

Since 11 September, Moscow has been determined not to negotiate with the rebels - a determination that only hardened after the Moscow theatre siege.

Instead of cultivating moderates like Ahmed Zakayev - the only rebel leader they have held direct talks with in recent years - Russian officials have gone all out to have him arrested and extradited.

Mr Putin's popularity has soared as a result of the hard line he took over the siege and its aftermath.

The Kremlin does have a plan to hold elections in Chechnya, and to use the new elected body to represent the Chechen people in talks on the republic's future.

The risk is, however, that the body will be seen by the rebels and their supporters as just one more extension of Moscow's rule - and that it will become a new target.