BERLIN (Reuters) – Police in the German city of Hamburg used pepper spray on protesters on Saturday and were ready to deploy water cannons as some demonstrations in support of U.S. anti-racist protests against police brutality turned ugly.

Hamburg police tweeted that several hundred “hooded and aggressive people” had put police officers under pressure in the city center, adding: “We have already had to use pepper spray. With all due respect for emotions: attacks on police officers are unacceptable!”

At another location nearby, they said some 350 people were standing in front of police water cannons. “We regard this as an unauthorized (i.e. forbidden) meeting and now we are calling via loudspeaker announcements for people to leave.”

One police officer was injured, the police added.