The general was defence minister under President Boris Yeltsin in 1992-1996 and was one of the decision-makers behind the first war Moscow launched, in December 1994, to defeat separatist forces.

Tens of thousands of people, many of them civilians, were killed before the signing of an August 1996 treaty that called for the withdrawal of federal forces and left the region in the hands of separatist leaders.

Grachev died at the Vishnyevsky military hospital outside Moscow.

Federal forces returned to Chechnya in 1999, beginning another devastating war that helped propel Vladimir Putin to Russia's presidency and restored Russian rule over the region but also fuelled an Islamist insurgency that persists today.

Grachev was dogged by accusations of involvement in corruption linked to the Soviet withdrawal from East Germany.

A journalist who had linked Grachev to corruption in the military, Dmitry Kholodov, was killed by an exploding briefcase in 1994, and his newspaper pointed the finger at Grachev.

Grachev was not charged in connection with Kholodov's killing, but when testifying as a witness he acknowledged using harsh words about the journalist when speaking to subordinates.

It is one of the many killings of Russian government critics that remain unsolved years later.