A masked raider seized hostages at a children's clinic in southern Russia and threatened to blow it up before escaping police negotiators, a senior official said.
The man walked into the clinic in mid-afternoon and threatened to blow it up with hand grenades unless he was given $5 million, Mr Boris Dzgoyev, Emergencies Minister in North Ossetia region,said from the city of Vladikavkaz.
No political demands were made.
With 18 people held hostage in the clinic, mostly women and children, police gave the man the equivalent of about $65,000 and agreed to take him in a car to another building he said was packed with explosives.
"As he was being driven to the second building where he said the bomb had been planted, the man forced those escorting him out of the car and drove off," Mr Dzgoyev said.
"The man is being sought and additional police have been dispatched to the railway station and airport, but his whereabouts are for the moment unknown."
Mr Dzgoyev said the region's Deputy Emergencies Minister was among those escorting the gunman in the car.
North Ossetia lies near separatist Chechnya in Russia's volatile North Caucasus region, the scene in recent years of numerous hostage-takings and other violent crimes - many with political motives.
Gunmen demanding the release of four men convicted of hostage-taking in 1994 seized a bus last July with 41 people on board and took them to a regional airport. Commandos then stormed the vehicle and killed one of the hijackers.
Meanwhile, Russian prosecutors yesterday demanded that parliament strip a senior pro-government lawmaker of his immunity from prosecution after accusing the deputy of corruption and fraud.
Prosecutors accuse Mr Vladimir Golovlyov, the deputy head of the State Duma lower house of parliament's budget committee and a member of the pro-Kremlin Union of Rightist Forces, of "illegal financial activity", or fraud.