Transcript for Anti-terror police investigate an ax attack at a German train station

Thursday night, and we are following a developing story coming in tonight. Police and special forces moving in after an ax attack at a busy and crowded train station in Germany. These cell phone images coming in from inside that station tonight. Amid reports of a man swinging an ax, several people injured in the attack. Authorities on the scene at this hour. At least one suspect is under arrest. ABC's Alex Marquardt leading us off with the images congreming in now. Reporter: Special police forces on the scene of the attack tonight. Investigating after five people were wounded, one seriously, by an ax-wielding attackerer. Trails of bloods on the floor. Shocked commuters huddled over the wounded. The attack taking place around 9:00 P.M. No one was killed. The station was shut down, cordened off by police, and helicopters hovered overhead. Bruno Macedo was on the train at the time. We're not stopping at the station. The station is closed. Reporter: A short time later, police confirming one arrest was made. The identity and motive of the attacker, still unknown. Dozens of officers search the train station and nearby businesses for possibly additional suspects. Across Europe, governments are on a heightened state of alert after a number of terror attacks over the past two years. Recently, attackers have went back to cruder methods. Last summer, ISIS claimed responsibility after an Afghan teen carried out an ax attack on a train elsewhere in Germany. Alex joins us live, and no claim of responsibility and no word on a motive tonight? Reporter: No claim of responsibility, David, and just a short time ago, the police put out a statement saying the suspect is in the hospital after

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