A plane forced to land in Iran after it accidentally entered Iranian airspace was a Hungarian aid plane, and not a U.S. aircraft as originally reported Tuesday by a state news agency, FOX News confirmed.

The semi-official Fars news agency in Iran reported Tuesday that a U.S. Military plane with American personnel on board was forced to land there.

But the U.S. Defense Department told FOX News that there was no evidence that the Iranian reports were true and was looking into the incident.

"We're looking into the various and conflicting reports coming from the Iranian "news" agencies, but do not have any information at this time that would lead us to believe they are correct," National Security spokesman Gordon Johndroe said.

"The Iran news agency is sending mixed signals," White House press secretary Dana Perino added. "There was no U.S. aircraft involved."

Iran also denied the reports.

The aircraft was a Hungarian aid plane with no Americans on board, a senior Iranian official told FOX News' Amy Kellogg in Tehran, adding that the incident took place on Sept. 30.

Fars reported that Iranian fighters guided the plane to an Iranian airport, where the passengers were questioned and released a day later.

Click here to read more on the Memri Iranian Media Blog.

FOXNews' Jennifer Griffin, Amy Kellogg and The Associated Press contributed to this report.