WASHINGTON  —  U.S. and Austrian authorities have arrested two Iranian men on charges of attempting to illegally export thousands of sophisticated American night-vision (search) systems for Iran's military, U.S. officials said Friday.

The alleged transactions were eventually expected to involved about 3,000 of the advanced helmet-mounted Generation III systems, which can amplify even faint starlight so that soldiers can see to fight in the dark.

"Sophisticated night vision systems allow U.S. troops to own the night, giving them a key advantage over their opponents during night-time combat. In the wrong hands, these night vision systems pose a threat to our troops around the world," said Michael J. Garcia, chief of U.S. Immigration and Customs Enforcement (search).

The two suspects, Mahmoud Seif (search) and Shahrzad Mir Gholikhan (search), were arrested earlier this week on export violation charges in Vienna, Austria, by U.S. and Austrian authorities shortly after they arrived to pick up their first batch of night-vision equipment. The investigation dates to August 2002 and involves ICE, the Defense Criminal Investigative Service and Austrian security personnel.

Exports of such advanced military equipment from the United States is forbidden without permission from the State Department. Iran is also subject to sanctions that bar most other U.S. exports. Austrian laws also prohibit such technology transfers.

During negotiations for the night-vision systems, Seif and Gholikhan allegedly said they were working in direct contact with the Iranian goverment, ICE officials said.

The case marked the latest in a string of attempts by Iranians to illegally obtain advanced U.S. military equipment, which has also included several recent efforts to buy components for missiles, helicopters and jet fighter aircraft.