Russian police on Sunday freed the son of software tycoon Eugene Kaspersky after a five-day kidnap ordeal, ending one of the highest-profile abduction dramas in the country in recent years.

Police officers, agents from the Federal Security Service (FSB) and the special OMON police squad freed Ivan Kaspersky, 20, in the Moscow region, Moscow police spokesman Viktor Birukov told Russian news agencies.

Reports said that officers posing as middlemen who were to hand over a ransom lured the kidnappers into a meeting and then arrested them.

Birukov said that five people had been detained on suspicion of organising the kidnapping of the son of the founder and general director of global computer anti-virus giant Kaspersky Lab.

"The condition of his (Ivan Kaspersky's) health is satisfactory," Birukov added.

The incident had been kept closely under wraps by the authorities and Birukov's comments were the first official confirmation that Ivan Kaspersky had even been abducted.

Unofficial reports had said last week the mathematics student at Moscow State University was abducted on April 19 while on his way to his work experience job as a programmer in the city.

Confusingly, a tabloid news website had reported on Friday that Ivan Kaspersky had already been released and a ransom had been paid for his liberty.

Reports said that the kidnappers had telephoned Eugene Kaspersky while he was in London earlier this week to make a ransom demand of three million euros ($4.4 million). He then immediately flew to Moscow.

But security sources quoted by the Interfax news agency vehemently denied any money had been handed over and said the release had been due to a sophisticated operation by the police.

"The kidnappers were forced into an error," the source explained.

"They were promised money but when the time came to hand over the funds the middleman was arrested and subsequently other perpetrators of the crime as well. Ivan Kaspersky himself was freed," the source added.

The source said the suspected mastermind was a figure with a previous conviction.

Neither weapons nor force were used in the liberation operation, sources said.

Ivan Kaspersky was later reunited with his parents and is in a "safe place", another source told Interfax, adding that while there was no evidence of physical injury it could not be excluded that he had received a psychological trauma.

Eugene Kaspersky, 45, co-founded Kaspersky Lab in 1997, building on a decade of research into computer viruses. The company has emerged as one of the world's leading anti-virus software firms.

His fortune is valued at $800 million by Forbes magazine, making him the 125th richest man in Russia.

The kidnappings of children of prominent businessmen is not uncommon in Russia, although Ivan Kaspersky was the most prominent victim yet.

In 2009 criminals held the son of a vice president at state oil firm Rosneft, Mikhail Stavsky. He was freed unharmed after a three-month ordeal.

Viktoria Kisluk, the 16-year-old daughter of a top manager at Russia's biggest private oil firm Lukoil, is still missing after vanishing in the Moscow region in March.

Kaspersky studied computer science, cryptography and mathematics at a Moscow institute used by the KGB intelligence service to train its staff.

He later worked at a defence ministry research institute until 1991, where he first began writing anti-virus programmes.

Kaspersky co-founded the company with his wife Natalya Kasperskaya. The couple are divorced.