The head of Russia's state-controlled electricity monopoly, Anatoly Chubais, has survived an assassination attempt.
Mr Chubais oversaw Russia's privatisation programme
Police said gunmen opened fire on his motorcade and also detonated an explosive device in the Moscow ambush.
Mr Chubais, who oversaw Russia's privatisation programme in the 1990s, was unhurt and continued to work after the attack, his spokesman said.
A retired army explosives expert has been arrested after detectives linked his car to the ambush, reports say.
The former deputy prime minister played a key role in the much criticised sale of Russia's natural resources to a select group of Russian businessmen - the so-called oligarchs.
Mr Chubais, 49, also ran former President Boris Yeltsin's successful re-election campaign in 1996, before becoming the chief of Unified Energy System in 1998.
He has also continued to play an active role in Russia's politics as one of the leaders of an influential liberal party - the Union of Right Forces (SPS).
Mr Chubais' two-car motorcade was attacked at about 0930 local time (0630 GMT) shortly after he left his country home outside Moscow, police said.
Police launched a manhunt for the attackers
"The explosive device went off between the two cars," a police spokesman said.
Police said that two unidentified gunmen clad in combat fatigues then sprayed the armoured cars with automatic fire.
Mr Chubais' BMW immediately sped off the scene, while bodyguards in the second car returned fire, forcing the attackers to flee, police and witnesses said.
No-one was hurt in the attack, police said.
Russian news agencies reported that police arrested the retired army colonel, who has a dacha in the same village as Mr Chubais, after tracing a car they suspected was used as a getaway.
Authorities searched his dacha as well as his son's Moscow apartment.
Russia's leading liberal politician Irina Khakamada said the attack was most likely linked to the reform of the power grid monopoly.
"It must have been linked to difficult processes of redistribution of UES assets," Ms Khakamada told Russia's Ekho Moskvy radio station.
But Boris Nemtsov, on the SPS's leaders, said that it was "clear to me the attempt on his life had political roots".
Mr Chubais himself appeared to acknowledge both possibilities.
"I understand quite clearly, who could have organised today's assassination," he said in a statement, without giving any names.
"The main thing I can say today is that everything I have done - regarding both the reform of the country's energy sector and the unification of democratic forces - I will continue to do with redoubled energy," the statement said.
Mr Chubais has in the past acknowledged that he has no shortage of enemies who have threatened to assassinate him.
"They've promised to drag me by my feet to the walls of the Kremlin, to draw and quarter me and then behead me on Red Square, to disfigure me with acid and many other things," he told Russia's Izvestia newspaper in 2001.