Two Russian intelligence agents have been charged in Qatar with the murder of Chechen rebel figure Zelimkhan Yanderbiyev, local officials say.
Mr Yanderbiyev had just returned to his car after attending Friday prayers
The men were detained five days after Mr Yanderbiyev, wanted by Moscow for terror offences, was killed by a car bomb in the Gulf state's capital Doha.
Three Russians were initially detained but the third has been since released.
Confirming that the detainees are anti-terrorism agents, Russia condemned the arrests as a "hostile move".
Russia has denied any involvement in the killing of Mr Yanderbiyev on 13 February.
Acting Foreign Minister Igor Ivanov told the Qatari ambassador in Moscow on Thursday that the detainees were "members of the Russian special services... linked to the battle against international terrorism".
"The insinuation of the Qatar authorities cannot be seen as anything but a hostile move," he said, going on to suggest the Qatari authorities had "practically kept Yanderbiyev under protection".
Mr Ivanov said the Russian detainees had been subjected to "rough physical force".
Mr Yanderbiyev was killed in a car bomb blast as he left a mosque after prayers in Doha.
Russia had been seeking Mr Yanderbiyev's extradition
He had been living in Qatar for three years and Moscow had repeatedly sought his extradition.
Mr Yanderbiyev briefly took over as Chechen president in 1996 after the death of Dzhokhar Dudayev in an explosion in Chechnya.
He was viewed as a key figure behind the 1999 incursion by Chechen rebels into the neighbouring Russian region of Dagestan.
He was also suspected of links to the siege of a Moscow theatre in October 2002 which left 130 hostages dead.
Mr Yanderbiyev was considered a key link in the Chechen rebels' fundraising network from abroad.
His death occurred one week after a bombing in the Moscow metro which killed 41 people and wounded more than 100.
President Vladimir Putin blamed Chechen rebels for the blast.