Russian forces are claiming to have killed 73 Chechen rebels and taken another 20 prisoners in a major operation in the separatist republic.
Meanwhile, two servicemen who had been held by Chechen rebels were freed, the Interfax news agency reports.
The news agency says, quoting the office of Mr Sergei Yastrzhembsky, the Kremlin's official spokesman on Chechnya, that rebel leader, Mr Ruslan Chilayev, was among those killed in the operation.
The reports do not specify where or when the operation took place or give any further details, other than saying some of those killed were mercenaries.
Details on the release of the servicemen are also sketchy. Interfax says the two had been taken hostage in the city of Urus-Martan and then taken to a neighbouring republic.
Both sides in the conflict are believed to frequently exaggerate casualty figures and claims can rarely be independently confirmed.
Russian troops withdrew from Chechnya in 1996 after rebels fought them to a standstill in a 20-month war.
They returned in September 1999 following terrorist strikes blamed on separatists, in which some 300 people were killed.
Wide-scale offensives ended last year, but rebels have continued to fight Russian forces with sniper fire, ambushes and mine explosions.
PA