TEHRAN (AFP) - Iran said on Tuesday it was "unaware" of a retired U.S. FBI agent who the United States says went missing last month during a private visit to the Islamic republic.

"I am unaware of this issue and read the news on websites," the student ISNA news agency quoted Intelligence Minister Gholam Hossein Mohseni Ejeie as saying.

The United States said earlier this week it had asked Tehran for information about the missing man, whose name and age have not been disclosed.

"The issue might be followed through the foreign ministry and the intelligence ministry plays no role," he said, responding to a question whether Washington was pursuing the case via the Swiss embassy which looks after U.S. interests in Iran.

U.S. officials have said the man went missing while visiting Kish, a small island of Iran's southern coast that has grown into a major resort and free trade zone. Press reports said he was researching a documentary.

Earlier on Tuesday an unnamed local official said "there is no concrete evidence that a U.S. citizen has entered Kish".

"This is worthless news. Unfortunately this news is published with a political aim and has no professional value," the state news agency IRNA reported.

"Instead of fabrication it would be better for the United States to give evidence regarding the identity and flight information so our local officials can investigate the matter," the official added.

State Department spokesman Sean McCormack said on Tuesday that Washington was still waiting for Iran's response to a request for information about the retired agent, made through the Swiss embassy in Tehran.