United Nations Secretary-General Ban Ki-moon has launched an investigation into how vials of a potentially hazardous chemical, confiscated in Iraq, ended up stored in a U.N. office for more than a decade.

The secretary-general's office issued a statement Friday saying two of Mr. Ban's aides have canceled travel plans so they can remain at U.N. headquarters to monitor the situation over the next few days.

On Thursday, U.N. officials announced the discovery of several vials of a decade-old, suspected chemical warfare agent from Iraq, inside a box of items stored at one of its New York buildings. They said there is no danger to the public.

The vials were determined to contain a chemical called phosgene, widely used as a chemical weapon during World War I.

The box, thought to contain only documents, was found at a building near, but not on, the main U.N. campus. The building served as headquarters for UNMOVIC, the U.N. organization that tracked Iraq's past use of weapons of mass destruction.

A spokeswoman said the room where the vials were found has been cordoned off, and that no toxic fumes have been found in the air.

Another official said staffers searched the rest of the building but found no more potentially hazardous materials.

Some information for this report was provided by AFP and AP.