Alexander Korshunov, director for business development at Russia's United Engine Corporation (UEC), was detained at an airport in Naples on Aug. 30 after Washington issued a warrant for his arrest.

UEC produces engines for civil and military aircraft as well as power turbines. Russian state conglomerate Rostec, which owns the engine maker, said Korshunov was innocent of any wrongdoing as did UEC, Russian news agencies reported.

Italy's foreign ministry said it had no immediate comment to make on the case.

Speaking at an economic forum in the Russian Far East, Putin said the arrest looked like it was motivated by what he called unfair competition.

"This is a really bad practice," Putin said. "In this case we're dealing with attempts at dishonest competition."

Putin said UEC had developed a new Russian engine and concluded a contract with an Italian consulting firm. "It's a normal global practice. It's open commercial work with European partners," said Putin.

Russia has repeatedly criticised the United States for requesting that Russian citizens be detained in third countries.