WASHINGTON (AP) -- The Pentagon accidentally sold to the public more than a thousand aircraft parts that could be used on the F-14 fighter jet -- a plane flown only by Iran -- after saying it had halted such sales, government investigators say.

In a report obtained Wednesday by The Associated Press, the U.S. Government Accountability Office, the investigative arm of Congress, says the Defense Department has greatly improved security in its surplus sales program to prevent the improper selling of sensitive items.

However, GAO investigators found that roughly 1,400 parts that could be used on F-14 "Tomcat" fighter jets were sold to the public in February. That occurred after the Pentagon announced it had suspended sales of all parts that could be used on the Tomcat while it reviewed security concerns.

Iran, trying to keep its F-14s flyable, is aggressively seeking U.S. components for the jets.

The Pentagon's surplus sales division -- the Defense Reutilization and Marketing Service -- told investigators the parts were sold because it failed to successfully update an automated control list and remove the aircraft parts before they were listed on its Internet sales site.

The GAO's investigation focused on F-14 parts.

"One country with operational F-14s, Iran, is known to be seeking these parts," Greg Kutz, the GAO's managing director of special investigations, wrote in the report. "If such parts were publicly available, it could jeopardize national security."

The GAO report was expected to be released later Wednesday.

The Defense Department said in January that it was suspending sales of all F-14 parts, including those that could be used on multiple types of aircraft, while it reviewed security. The department's announcement came a few weeks after an investigative report by The Associated Press found weaknesses in surplus-sale security that allowed buyers for Iran, China and other countries to surreptitiously obtain sensitive U.S. military gear including missile components and parts for the Tomcat and Chinook helicopter.

Legislation that would ban the Defense Department from selling F-14 parts has cleared the House and is pending in the Senate.

(Copyright 2007 by The Associated Press. All Rights Reserved.)