Pentagon: Inventory ordered of all U.S. nukes by Barbara Starr FROM CNN

The order comes in the wake of the discovery last week that four nuclear warhead fuses were accidentally shipped to Taiwan in 2006.

Gates' memo, issued Wednesday, calls for all items to be accounted for by serial number.

Pentagon officials said at a news conference Tuesday that Gates would call for the review in addition to a full investigation into how the shipment to Taiwan from a Defense Logistics Agency warehouse happened 18 months ago.

The inventory review, which will involve thousands of items, is due to Gates in 60 days. Pentagon officials said the request was ordered, in part, because this latest incident comes after the August 2007 accidental flight of six nuclear-tipped cruise missiles on a B-52 bomber across the country.