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

The 24-year-old woman had found the ammunition during a hike near the Dachstein peak in the Austrian Alps, police said.

She washed the 30-centimetre-long grenade in her hotel room before putting it into her suitcase.

At the airport, the woman asked customs officials whether she could take the find with her.

The airport's departure hall was temporarily cordoned off while munitions specialists confiscated the unexploded ordinance.