A man spouting racist insults allegedly confronted two Syrian teenagers in northeastern Berlin and punched them in the face, authorities said Saturday.

He hit the girls, aged 15 and 16, "with his fist several times ... before fleeing into a shopping arcade," police alleged in a statement. Both girls were taken to hospital for treatment.

Hours later, a woman reportedly attacked a 12-year-old girl in the southeastern suburb of Neukölln. Officers alleged the suspect tried to tear off the girl's headscarf, pulled her hair and threatened her with pepper spray. The woman also allegedly attempted to stab the child with a syringe filled with what appeared to be blood, police said. 

Officers from the state security police are investigating the incidents, which took place late Friday.

The suspected hate crimes highlight tensions over migration in Germany. Last month, a 50-year-old German man was charged with attempted murder after he deliberately drove his car into foreigners in the western cities of Bottrop and Essen. Eight people were injured in the New Year's Day attack, including a 4-year-old Afghan boy and a 10-year-old Syrian girl.