MOSCOW, June 1 (Xinhua) -- Russia's Federal Security Service (FSB) said on Thursday that it uncovered a reconnaissance operation by U.S. intelligence agencies carried out with Apple mobile devices.

"The FSB, together with the Russian Federal Protective Service, uncovered an intelligence operation by U.S. intelligence agencies with the use of Apple mobile devices," it said in a statement.

"In the course of securing the Russian telecommunications infrastructure, anomalies were identified that are specific only to users of Apple mobile phones, and they are caused by the operation of previously unknown malicious software that uses software vulnerabilities provided by the manufacturer," it added.

According to the FSB, several thousand phones were affected.

In addition to domestic subscribers, foreign numbers and subscribers using SIM cards registered with diplomatic missions and embassies in Russia were affected, it said.

"The information obtained by the FSB demonstrates close cooperation between Apple and the U.S. national intelligence community ... and confirms that Apple's declared privacy policy is not true," said the FSB.