By Stephen Dalziel BBC Russian Affairs analyst

The Russian President, Vladimir Putin, will be as relieved as his fellow countrymen that the siege of the Moscow theatre was ended with so many lives being saved.

But now the difficult questions begin.

The first question which will have been constantly in Mr Putin's mind ever since he was called to the Kremlin by news that the theatre had been stormed by rebels on Wednesday evening is, how could such a thing happen in the middle of Moscow?

The hostage drama terrified many in Russia

As a former member of the secret police, the KGB (now the FSB), Mr Putin will want to know where the intelligence-gathering process broke down.

All people who look as though they might come from the Caucasus have been regarded with suspicion in Moscow ever since the Chechens were accused of blowing up two blocks of flats in Moscow in September 1999 - the incidents which sparked off the second Chechen campaign.

Reputation at stake

Caucasians in Moscow can expect to be stopped and have their documents checked every day.

So how could several dozen of them have banded together to break into the theatre?

And how were they able to bring so many explosives to the building, when checks on transport are a common feature of everyday life in the Russian capital?

Sackings can be expected in both the FSB and the Interior Ministry, which is responsible for the police.

But this question of internal security is secondary to the big problem facing Mr Putin: what now for Chechnya?

What the siege has done is to bring this hitherto largely forgotten conflict to the forefront of world attention.

In itself, that has already destroyed much of what Mr Putin had been trying to do for a long time.

Decisive action

Claims by the Russian authorities that they have had the situation in Chechnya under control have clearly been nonsense.

But you can get away with speaking nonsense if no-one bothers too much about the subject. Now the pressure will be on Mr Putin to take decisive action in Chechnya.

That decisive action could take one of two forms. He could step up the military offensive. Or he could enter into some form of dialogue with representatives of the Chechen rebels.

Rebel leader Barayev was killed in the gun battle

If Mr Putin goes for the former, it will show that he has learnt little about the situation in Chechnya and the real nature of the problem.

He has a demoralised army which has committed gross human rights violations in Chechnya already, and which has shown itself to be incapable of coping with the type of guerrilla warfare being waged by groups of Chechen fighters.

Furthermore, the Chechens have shown in both the first, failed, Russian military campaign of 1994-1996, and in the current campaign, that they are well capable of using the mountainous terrain in the south of their republic to their own benefit.

So dialogue would seem to be a more positive way forward.

Further bloodshed

For this, Mr Putin and the Russian leadership would have to take the embarrassing step of granting recognition to the elected Chechen President, Aslan Maskhadov, or his representatives.

Moscow did acknowledge Mr Maskhadov's authority before the troops were sent back in in 1999, but has since denounced him as a "terrorist".

There is a third option. To carry on the campaign as they have been conducting it for the last year or so.

If Mr Putin does this, a genuine solution to the Chechen problem will be as far away as ever. More Russian soldiers will be killed.

And now that Muscovites have had the war brought to their own doorsteps, that is a price which Russians may not now be prepared to pay.