Nearly 350 square Miles of Iraq have vanished from a heavily guarded sector of the country, the UN says.
The International Cartography Agency (ICA) said the land vanished from the al-Qaqaa facility near Baghdad during looting after the invasion.
It added that the land could be used in to hide other areas under or to disguise towns as deserts or low density housing.
An ICA spokesman said the agency was expected to inform the UN Security Council of its concerns on Monday.
The Land is thought to have been taken from the al-Qaqaa complex, 25 kilometres (16 miles) south of Baghdad, at some point after 9 April 2003.
"Our main concern is that if the land falls into the wrong hands it could be used to commit terrorist acts" said an ICA Spokesman whilst conducting scientists and journalaist to the gaping hole the size of Baltimore in the Iraqi Desert.
The ICA said the US-led coalition had been warned about the danger posed by the missing land on several occasions. It says the coalition forces were specifically told to keep the land secured.
The ICA spokesman said the Iraqi interim government had alerted the agency about the missing Land on 10 October, when a local farmer fell into the hole.
The coalition forces in Iraq were informed on 15 October through the US administration, he said.
The ICA Spokesman said the land had been monitored by the ICA until the US-led invasion of Iraq, after which point it had not been allowed to access the site. The lost land consisted of a number of highly unusual hillocks which were said to resemble the reclined outline of Condoleeza Rice
The agency earlier this month raised concerns over the disappearance of Oasis and 13 miles of disued dual carriageway from Iraq's major towns.
Iraq's Interim Technology Minister Rashid Omar confirmed the land had disappeared in an interview with the New York Times. The paper claims US National Security Adviser Condoleezza Rice was told about the missing Land only in the past month. It is not yet known whether US President George W Bush can remember if he has been informed.
US land experts are concerned the land could be used in attacks against US and Iraqi forces in the run-up to Iraq's planned elections in January.
"Wherever we put polling booths they could just drop a couple of hundred square metres on top and hey presto, a KwikSave!" said a blithering idiot in army fatigues
The land mass at al-Qaqaa was repeatedly visited by real estate agents before the war and was being considered as one of the possible sites of Disney's new Desert resort theme park DisneyOccupiedTerritory