Police responding to Amsterdam's Leideplein entertainment district found a "small explosive" on the Kleine Gartmanplantsoen. The explosive was discovered in a hotel and catering facility, police said on Twitter at about 5 p.m. on Tuesday. An explosives disposal unit was en route to the scene, police added.

Witnesses said the device was actually a hand grenade, and that it was thrown into the area nightspot, Cafe In The City, according to broadcaster AT5. Bianca Hoorn was sitting in the cafe drinking tea when she was told by a worker to quickly leave the building. The 35-year-old woman told a Parool reporter that she had to dodge the suspected explosive on her way out. "It was black, oval-shaped, smooth, and had something that looked like a golden latch. It looked fake, like a giant lighter," she added.

"Then again, I have also never seen a real bomb."

Much of the area surrounding the Leidseplein was secured by police around the beginning of the evening rush hour period. All road traffic, trams and pedestrians were redirected around the scene. Police did not say when they expected the area to be re-opened.

Cafe In The City opened its doors on the Kleine Gartmanplantsoen last autumn. It is located on the premises of the former restaurant Blinq.

