Iranian cyberattacks targeting the social media and email accounts of White House officials have spiked in recent weeks, reports the Wall Street Journal, citing anonymous government officials.
“We’re aware of certain reports about possible cyber activity involving Iran,” a State Department official told Fortune, declining to comment on the Journal’s report. “We are aware that hackers in Iran and elsewhere, often use cyber intrusions to gain information or make connections with targets of interest.”
The attacks reportedly targeted members of the Obama administration, State Department workers in the agency’s Office of Iranian Affairs and Bureau of Near Eastern Affairs, as well as journalists and academics. They are likely linked to the arrest last month of Siamak Namazi, an Iranian-American businessman who has promoted strengthening U.S.-Iranian relations.
U.S. officials believe the computer intruders are members of the Islamic Revolutionary Guard Corps (IRGC), a powerful Iranian military force that numbers more than 100,000. Though members of the unit regularly attempt to hack computer systems and accounts affiliated with the U.S. government and its staffers, officials say they have noticed an uptick in the digital attacks recently, according to the Journal.
The intelligence arm of the IRGC arrested the energy executive Namazi in Tehran a few weeks ago—a move that foreign relations watchers have viewed as a sign that hard-liners in the Iranian regime are seeking to keep foreign investments out of the country after it recently struck a landmark nuclear deal with the U.S. and others.
Despite the controversial nuclear accord providing relief to Iran from U.S. economic sanctions, some U.S. officials have called for stricter measures to be placed on the IRGC as a result of Namazi’s detainment.
The Iranian hacking unit might be interested in compromising Namazi and others’ social networks in order to build an espionage case against them. As the Journal explains:
Computer experts have noted that by hacking a target’s contacts—particularly their social-media accounts—the number of people associated with that target can grow exponentially. If the target’s Facebook account has 200 friends, and each of those had 200 friends, a skilled hacker could potentially gain access to 40,000 users—even if most of them aren’t actually associated with the original target.
In so doing, the Iranian hard-liners could try to amass a case based on people with some digital affiliation to an individual who, in reality, are several times removed as friends of Facebook friends or followers of Twitter followers, according to computer experts.
An Iranian diplomat told the Journal that the country has repeatedly been falsely accused of waging cyberwar.
Fore more on Iran read this contributed “Guide to doing business in Iran.” While you’re at it, go ahead and subscribe to Fortune’s daily business-tech newsletter Data Sheet, and watch this video about Iran from Fortune’s Most Powerful Women Summit.