U.S. officials said that in recent weeks Iran has escalated its cyber attacks, targeting the U.S. military and hacking unclassified Navy computers, according to The Wall Street Journal.
This news came on the same day that President Barack Obama and Iranian President Hassan Rouhani spoke by phone, the first such high-level communications between the nations in more than 30 years.
(Read more: Obama, Iran's Rouhani speak on nuclear issues NBC News)
Officials said that cyberintrusions were committed by hackers who work directly for the Iranian government or received an approval of Iranian leaders, The Wall Street Journal reported. The unclassified network they hacked was apparently used for email and internal intranet.
If confirmed, this would be one of the most serious breaches of U.S. computer systems by Iran.