U.N. inspectors found vials of poisonous gas in one of their offices near U.N. headquarters, a spokesman announced today.

Two plastic packages containing gram-sized amounts of liquid were discovered last week as U.N. inspectors were archiving old files in a room at 866 East 48th St. Yesterday, an inventory report revealed that the packages contained the chemical agent phosgene, an old warfare agent that was used in a majority of chemical deaths during World War I.

The chemicals were recovered in 1996 from a former Iraqi chemical weapons facility, Al Muthanna, and sent to the wrong office, the U.N. said in a statement. Normally, they would have been sent by military transport to a laboratory equipped for analysis.

The U.N. said that chemical weapons experts had sealed the packages and placed them in a secure location on the sixth floor. The floor was evacuated this afternoon as a Hazardous Materials unit responded to remove the materials and bring them to a military facility outside of New York, police said.

The air surrounding the packages was found to be free of toxic vapors, police said.

“The materials pose no threat to the public,” a police spokesman, Paul Browne, said in a statement.