Iranian authorities said Nizar Zakka was linked to the U.S. military and intelligence agencies.

Iranian authorities have arrested an American-Lebanese man who they say was linked to the U.S. military and intelligence agencies, state broadcaster IRIB said on Tuesday.

It named the man as Nizar Zakka, an IT expert who Lebanese media reported last week had disappeared on Sept. 18 after attending a conference in Tehran.

The report, which cited informed sources, is the first official confirmation of his arrest.

“Nizar Zakka has deep ties to the U.S. intelligence and military establishment,” IRIB quoted an unnamed source as saying.

There have also been reports that Iran has arrested U.S.-Iranian citizen Siamak Namazi, a Dubai-based businessman who disappeared in mid-October while visiting family in Iran. Reuters has not been able to confirm those reports.

Intelligence Minister Mahmoud Alavi said on Monday the ministry had been discussing ways to combat foreign influence in the country as Tehran begins to implement a nuclear deal that will lift sanctions and open Iran to foreign businesses.

The authorities also arrested two Iranian journalists on Monday. The head of the judiciary dismissed international condemnation of what appears to be a crackdown on local writers and artists.