An air force spokesman said Major-General Konstantin Dementyev was killed when his car was raked with small arms fire from another car.

General Dementyev's driver also died in the attack on Sunday evening, near Arkhipovka village in the Smolensk region. A second passenger was wounded.

Dementyev was deputy head of Russia's strategic long-range air force.

He was returning from a holiday in Belarus on the Minsk-to-Moscow highway when he was shot, the spokesman said.

An official at the regional prosecutor's office, quoted by Itar-Tass news agency, said: "A suspect has been detained. His possible involvement in this crime is being investigated now."

'Unintended victim'

Investigators said the general's car was fired upon by at least two attackers in another vehicle.

They said the attackers approached the car after firing on it, and then left.

The survivor was described in one report as a 67-year-old military pensioner.

The regional prosecutor's office said the general was not thought to be the attackers' desired target.

Itar-Tass said investigators are pursuing several leads, including investigating whether the attack had anything to do with the dead driver's work for a security firm.

It quoted "a source close to the investigation" as saying Gen Dementyev may well have been "an unintended victim of the war between a bodyguard company in Smolensk and bandits".

It said both the Federal Security Service (FSB) and military counter-intelligence would take part in the investigation.