Iran said it has identified the perpetrators of a cyber attack of the country’s crude-oil industry, tracing them to the U.S., Fars News Agency reported, citing an official.

Two Internet protocols used in the attack against Iran’s oil ministry have been linked to U.S. addresses, Kamal Hadianfar, head of the country’s cyber police said today, according to the state-run news agency.

Iranian officials said in April they managed to contain a cyber attack that caused computer systems at the Oil Ministry and other related state-owned businesses to crash.

The hackers sought to infiltrate the ministry’s main servers on April 23 but failed, Fars said in today’s report. They only managed to access data of minor importance, it said.

To contact the reporter on this story: Ladane Nasseri in Dubai at lnasseri@bloomberg.net

To contact the editor responsible for this story: Andrew J. Barden at barden@bloomberg.net