Russian intelligence officers convicted in Qatar for the murder of Chechen ex-president Zelimkhan Yandarbiyev, have returned to Moscow.
Yandarbiyev was killed in a car explosion outside a mosque
Earlier Qatari officials confirmed that the two men would be handed over to
serve out the remainder of their life sentences in Russia.
Mr Yandarbiyev, who fled Chechnya after the start of Russia's second military campaign, died in a car explosion.
The case caused a diplomatic row between Moscow and Doha.
Mr Yandarbiyev served a brief term as an interim Chechen president after his predecessor, Dzhokhar Dudayev, was killed by a Russian missile in 1996.
Reputed as an Islamist radical, he then lost election to the moderate and then pro-Moscow Aslan Maskhadov.
After the Russian troops invaded Chechnya for the second time in 1999, Mr Yandarbiyev emigrated to Qatar.
Russia demanded his extradition on charges of terrorism and links to al-Qaeda, but Qatar refused.
Mr Yandarbiyev was killed by a bomb planted in his car when he returned home from a mosque in February.
Two bodyguards also died and his son was injured in the attack.
The Qatari authorities arrested and charged three Russian nationals with murder, but one was soon freed because of his diplomatic status.
The other two were sentenced to life by the Qatari court, which ruled that they were acting on the orders from the Russian government.
Moscow insisted that the men were innocent.
The case shocked Qatar - a tiny oil-rich state, closely allied to the US, which prides itself on its low crime rate and tight security.