Warily, when he visited Moscow last year, he agreed that the war in Chechnya was Russia's internal affair.

ECONOMIST: Ismail Cem, a Turkish strategist

Many are local and young, born when Russia first went to war in Chechnya in 1994, says Mr Shvedov.

ECONOMIST: Russia's north Caucasus

These are not people who fought in the war in Chechnya, they're not people who had any close, proximate relationship to that conflict.

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In the 1990s, Russia's war in Chechnya spilled into Dagestan.

BBC: Boston bombings: Pro-Tsarnaev posters in Chechnya

Some of the darkest pages in Boris Yeltsin's career were written a year later, in December 1994, when he launched a war in Chechnya which exposed and exacerbated the Russian army's weakness.

ECONOMIST: Russia’s flawed reformer | The

But Mr Putin needs to start, if only because it is hard to see how new powers for Russia's troops and law-enforcement agencies will succeed in ending the war in Chechnya, where any supposed limits on their old powers in the past were anyway ignored.

ECONOMIST: Do as you would be done by, damage as you would be damaged by

So he believes that maybe the quid pro quo for helping the Americans on all this - even if it is only limited help - will be to have less Western criticism of Russian action in Chechnya itself and the war there.

BBC: Jonathan Charles in Moscow

The Russian authorities had alerted US counterparts to the activities of Tamerlan Tsarnaev, whose family has its origins in the war-torn Russian republic of Chechnya.

BBC: CIA 'tracked Boston bomb suspect Tamerlan Tsarnaev'

The peace deal signed in 1996 that ended the war froze the question of Chechnya's status for five years.

ECONOMIST: Chechnya

Russian troops withdrew from Chechnya in 1996 after the first Chechen war, leaving it de-facto independent and largely lawless, but then rolled back three years later following apartment building explosions in Moscow and other cities blamed on the rebels.

NPR: Russia's Chechnya Has Seen Decades Of War, Terror