A large number, possibly hundreds, of shoulder-launched surface-to-air missiles have gone missing in Iraq since the fall of Saddam Hussein, a newspaper report said Wednesday, leading to hair-raising security issues for airports both in Iraq and across the world.

Missiles have been fired at military planes taking off and landing at Baghdad International Airport (search) several times since it fell to American forces in early April. All have missed. 

The knowledge that a large part of Iraq's surface-to-air missile arsenal has vanished, along with a handful of near misses in recent weeks, has kept the airport closed indefinitely even as foreign airlines clamor to secure commercial landing rights, according the New York Times.

Several hundred shoulder-fired anti-aircraft missiles have been discovered in Iraq. Countless others are still missing. The search is hampered by the fact that coalition authorities can only guess at how many surface-to-air missiles Iraq had.

 "We just don't know," one coalition official told the newspaper.

U.S. military aircraft are armed with anti-missile evasion devices, and pilots are trained in evasion maneuvers, but few commercial planes are similarly equipped.

The U.S. military is offering a $500 reward for each missile handed over to coalition forces (search) and has paid more than $100,000 in rewards to date, according to the Times. Considering that the weapons can bring in as much as $5,000 each on the black market, the $500 enticement might not be enough.

So far, about 320 of the shoulder-fired anti-aircraft missiles have been turned in, according to military spokesman Lt. Col George Krivo.

"We continue to get more every day," Krivo said. "The number does not include the many hundreds that we have found and destroyed as a result of patrols, raids and other military operations."

Almost as worrisome is that part of Iraq's missile arsenal could make its way across the country's currently leaky borders.

In Nov. 2002, a Soviet-designed surface-to-air missile was fired at an Israeli charter airliner taking off from Mombasa, Kenya, but it missed. Israeli airliners are rumored to carry anti-missile devices and their pilots trained in evasion.

Both the failed Mombasa attack and the simultaneous bombing of a nearby Israeli-owned beach resort were blamed on Al Qaeda.

Britain suspended all commercial flights to Kenya, a popular tourist destination, in mid-May of this year because of fear of missile attacks on planes. The ban was lifted in September.

Troops have unearthed several hundred Iraqi missiles, many at secret weapons disposal sites. On Tuesday in Taji, north of Baghdad, members of the 4th Infantry Division found 49 surface-to-air missiles in a hidden cache.

Military planes take off and land daily on Baghdad International's repaired runways, and Australian forces are operating its air traffic control, the Times reported.

Coalition authorities had hoped to open Baghdad airport to commercial service by mid-July. However, only one company — a Jordanian charter firm — operates flights to Baghdad.

A large number of Stinger surface-to-air missiles supplied to Afghan mujahedeen during the Soviet occupation in the 1980s have never been accounted for. Although Stingers have an effective working life of about seven years, unnamed military experts told the Times that proper care and maintenance could preserve them long beyond that.

Fox News' Molly Hennenberg, Catherine Donaldson-Evans and The Associated Press contributed to this report.