German police said Saturday that they have arrested a 61-year-old man after three people were wounded in a hand grenade and knife attack in Berlin.

Police said the attacker detonated the grenade in the entrance of an apartment building in the Reinickendorf neighborhood of the German capital on Friday night, wounding two women, aged 42 and 48, and a 61-year-old man.

The suspect then allegedly ran toward two of the victims and attacked and wounded them with a knife.

All three victims were taken to the hospital. The man suffered life-threatening injuries, police said in a statement.

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The attacker then fled. Police detained the suspect in a nearby garden later.

Police were still investigating possible motives for the attack and whether the suspect and the victims knew each other. They did not release any details on the attacker's identity or those of the victims as is customary in Germany.

German news agency dpa reported that the alleged attacker is a Serb and the two women also have Serbian nationality, while the wounded man is from Bosnia-Herzegovina.