NEW YORK - (AP) - Police say an employee doing gardening work dugup a garbage bag containing military-grade explosives at a historicManhattan cemetery last year but left it at the site. It remainedthere until a volunteer told authorities about it on Monday.

The C-4 plastic explosive is more powerful than TNT. It requiresa detonator, or cap, to explode and police said no caps were foundat the scene.

Police Commissioner Raymond Kelly said the worker dug up the bagat New York City Marble Cemetery in May 2009 or June 2009 but leftit sitting near a fence.

A volunteer cleaning up over the weekend found it, and initiallyleft it there before informing police Monday morning.

Kelly says the material is the same as what was used in the 2005London transit bombings.