A metal device in a suitcase exploded in the hands of a security guard who was inspecting it at Jordan's international airport Thursday, killing the man instantly, authorities said.

Police detained the suspected owner of the suitcase, a Japanese journalist, who told authorities he had no knowledge that he had an explosive device in his possession, said officials involved in the investigation.

The explosion wounded three other people, said Information Minister Mohammad Affash Adwan. Two of the wounded were guards, one in critical condition, Adwan said.

The journalist, identified as Hiroki Gomi of the Mainichi newspaper, told authorities he picked up the metal device as a "souvenir from the remnants of war on Iraq," Adwan said.

Adwan later told the official Petra news agency that the man said he bought the metal device from an Iraqi citizen in Baghdad and that he crossed Jordan's eastern desert border overland from Iraq on Monday.

"He told authorities he didn't know that it was an explosive device which hadn't detonated," Adwan told The Associated Press. He said the journalist would stand trial in Amman.

Security officials said the airport guard saw the metal device during the X-ray screening and asked the man to open his suitcase for a manual search.

The device exploded in his hands, killing him instantly, Adwan said.

Adwan said the bag was checked on an EgyptAir (search) flight to Cairo, Egypt, where the journalist was heading after an assignment to Iraq.

The Japanese journalist also had some other souvenirs from Iraq, such as antiques, rugs and paintings, a security official said on condition of anonymity.

He said authorities were conducting random checks on all luggage and areas in the airport's departure terminal, including a robot that was sifting through suitcases.

Panic ensued after the blast at Queen Alia International Airport (search), where passengers were being checked in or departing to various destinations, including France, Egypt, Lebanon, Israel and the United Arab Emirates.

Queen Alia Airport was one of the targets of a terrorist conspiracy foiled in November 1999. The plot involved 28 Arab men who planned attacks on U.S. and Israeli targets in Jordan during millennium celebrations. Jordan military court in 2000 convicted six of the accused to death and acquitted six others.