A US tourist triggered a security alert at Vienna airport when she tried to take a World War II grenade home in her luggage.

Returning home after her Austrian holiday, she pulled a hand bomb out of her bag at border control, which she washed in her hotel room before putting it into her suitcase.

She had asked the customs officers if she could take the “souvenir” home with her.

Officials quickly called the bomb disposal unit to remove and dispose of the 7.5 cm caliber dud tank artillery shell.

The incident shut down the arrival and luggage hall for 15 minutes. Police said at no time were passengers under threat.

The 24-year-old was reported to prosecutors for negligent endangerment and fined €4,000.