By attacking Grozny, the Russians are dramatically upping the stakes - and giving Chechens a vivid reminder of the bombardment of the city in the winter of 1994-5.

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That onslaught left thousands of dead and reduced the centre of the city to rubble.

So are the Russians planning another invasion - using air attacks to soften Chechen defences in preparation for ground troops, as they did in December 1994 ?

The evidence is mixed.

At least three senior Russian generals believe that it is time to launch a full ground invasion and reverse Russia's humiliating defeat in Chechnya in 1996, according to the Izvestia newspaper.

The newspaper added that the generals believe they have learnt military lessons from their previous defeat.

Some Russian generals are said to want all-out war

Furthermore, public opinion is also extremely hostile to the Chechens following the spate of bomb explosions in Moscow - even though no official proof has been presented of a Chechen connection.

But the 1994 invasion turned into disaster and eventually defeat.

The deaths of civilians and the slaughter of inexperienced conscripts led to an upsurge of popular anger in Russia.

Nor is there any reason to believe that the Russian military is better equipped or funded than it was last time.

Russian threat unifies Chechens

As for Chechnya, it is a divided society, with the government of President Aslan Maskhadov aspiring to independence from Russia but opposing the rebel groups led by the former commander Shamil Basayev.

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But the Russian threat is a powerful unifying factor - and, although it is still shattered from the last conflict, Chechnya does have two things in abundance: guns and young men prepared to use them.

So Moscow may decide it is too risky to send in the troops.

But its latest bombing tactics are unlikely seriously to damage the guerrillas, who are well used to evading Russian air attacks.