(CNN) A WWII bomb found by firefighters taking part in a diving exercise in a river in Frankfurt, Germany, was safely detonated Sunday.

The 250-kilogram (550-pound) bomb was discovered in Frankfurt's Main River , a tributary of the Rhine, on Friday. Around 600 residents were evacuated as bomb disposal experts detonated the bomb early Sunday.

Please note: A WW2 bomb in the Main is to be defused tomorrow, Sunday, 14th! Around the area (see interactive map https://t.co/wI5M5cndf4) both river Banks will be locked until the operation is completed. For latest information follow @Polizei_Ffm and @feuerwehrffm! Please share. pic.twitter.com/K1jOXjIorE — Frankfurt am Main (@Stadt_FFM) April 13, 2019

"I want to thank all the volunteers for their professionalism and their engagement -- And all the residents who had to leave their apartments for their cooperation and patience," Frankfurt Mayor Peter Feldmann tweeted.

"My thanks also to all the facilities in the city that gave the evacuees free admission to the open museums, the palm garden and the zoo," Feldmann said at a news conference.

People lined the river away from the explosion site and watched as large spout of water shot up out of the river when the bomb was detonated.

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