Italian police arrested a top executive of Russia’s state-owned aircraft-engine maker on U.S. charges that he tried to steal aviation secrets, the Justice Department said Thursday.

Russian President Vladimir Putin condemned the arrest as “bad practice” and said it could complicate relations with the U.S., which he noted uses Russian raw materials for its own aviation industry.

“Boeings are made from our titanium,” Mr. Putin told an economic forum in the Russian Far Eastern city of Vladivostok.

The Justice Department said that Alexander Korshunov, 57 years old, head of business development at United Engine Corp., was detained last week on his arrival at an airport in Naples, Italy, on a criminal complaint that the department released Thursday.

UEC produces engines for civil and military aircraft, as well as power turbines. The company is a subsidiary of the Russian state conglomerate Rostec, whose head, Sergei Chemezov, is a confidant of Mr. Putin and is subject to U.S. sanctions. The companies didn’t respond to requests for comment Thursday.