Washington - The Pentagon sold more than a thousand aircraft parts that could be used on F-14 fighter jets -- a plane flown only by Iran -- after announcing it had halted sales of such surplus, government investigators say.

In a report Wednesday, the Government Accountability Office of the United States, the investigative arm of the US Congress, said the Defense Department had improved security in its surplus program to prevent improper sales of sensitive items.

But 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 came 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 maintain its F-14s, is aggressively seeking components from the retired US Tomcat fleet.

The Pentagon's surplus sales division -- the Defense Reutilization and Marketing Service -- told investigators the parts were sold because it failed to 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. Iran is known to be seeking those, and if the parts were publicly available, it could endanger national security, Greg Kutz, the GAO's managing director of special investigations, wrote. Iran has managed to obtain US spares in the past, he said.

Kutz said he does not know if any of the Tomcat parts sold in February made it to Iran. The GAO forwarded details about some of the sales to federal law enforcement for possible investigation, he said.

"Overall I think it's a positive report, but there are still things that got out," Kutz said in an interview.

A Democratic senator said the report shows why legislation he proposed that would ban the sale of all F-14 parts is needed.

"The Pentagon's system is still riddled with holes," Oregon Sen. Ron Wyden said. "These are the very parts that they said they wouldn't be selling and they still are and so you've got to make sure the changes are going to actually have teeth and work."

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 the Pentagon reviewed security.

That announcement came a few weeks after an investigative report by The Associated Press found weaknesses in surplus-sale security had allowed buyers for Iran and other countries to obtain sensitive US military gear including missile components and parts for the Tomcat and Chinook helicopter.

The congressional investigators also looked at sensitive military leftovers in general that were supposed to be destroyed rather than sold in Pentagon surplus auctions.

In the first month of their inquiry, last September, they found the Pentagon had sold 295 items to the public that were supposed to be destroyed. But after that, though several items that were supposed to be destroyed were posted on the surplus Web site as for sale, they were spotted and removed before they were sold, the report said.

The military's surplus service told the GAO that between last August and May, about 2.4 million individual pieces of sensitive surplus were removed from public sale.

The new GAO report comes as a surplus dealer trade association accuses the Pentagon of overreacting to security concerns and wasting taxpayer money by junking thousands of items unrelated to the F-14. That includes leftover gear the group says its members used to buy and sell back to the military when it was needed quickly.

The Defense Department says the allegations are untrue. The surplus dealers want Congress to force the Pentagon to do a better job separating sensitive scrap from items that are safe to sell.

Wyden said he understands the group's concerns.

"I think our legislation speaks to some of their philosophy that the Pentagon has bumbled to the point where they can't make the distinction" between sensitive and innocuous surplus, Wyden said.

The F-14 legislation sponsored by Wyden and Democratic Rep. Gabrielle Giffords of Arizona has passed the House and is pending in the Senate.

Wyden said he will try to attach it to a defense funding bill that the Senate is expected to consider next month. The lawmakers sponsored the bill in reaction to the AP's story on surplus security.