The Atomic Energy Organization of Iran, the country’s top body overseeing its contested nuclear program, said email servers at one of its subsidiaries were subject to an "illegal infiltration” by an unknown group in a foreign country.

According to a statement on the website of the AEOI, a number of emails from the information technology unit of the Nuclear Energy Production and Development Co., which is responsible for making nuclear energy, were published online.

The announcement comes after a group called Black Reward claimed in a series of messages on its Telegram channel and on Twitter on Friday that it had hacked the AEOI as part of a campaign supporting anti-government protests currently gripping Iran.