The leader of Arab fighters in Chechnya, Saudi-born Abu al-Waleed al-Ghamdi, has been killed in the rebel Russian region.
Abu al-Waleed is said by the Kremlin to be among those behind a February bombing on the Moscow underground.
In March, Arab television channel Al Jazeera broadcast a videotape it said was by Abu al-Waleed vowing to stage a new wave of attacks inside Russia.
The Kremlin blames Chechen rebels for a spate of attacks including a suicide bombing which killed close to 50 people on a train in southern Russia before last December's parliamentary polls and the attack on the underground, which killed around 40.
The Kremlin believes Abu al-Waleed was also among those behind the 1999 apartment bombings across Russia that prompted President Vladimir Putin to send troops back into Chechnya.
