investigators were following every lead to determine the teenager's motive and it was too early to say whether he had an Islamist background. So far, it was understood that he had acted alone.

Herrmann confirmed in an earlier television interview that the teenager boarded the train in Ochsenfurt, where he had been staying with a foster family.

"He suddenly attacked passengers with a knife and an axe, critically injuring several. Some of them may now be fighting for their lives."

The Afghan national reportedly shouted "Allahu Akbar," Arabic for "God is great," before launching the attack, wielding a knife and axe.

"The perpetrator was able to leave the train, police left in pursuit and as part of this pursuit, they shot the attacker and killed him," a police spokesman said. On Tuesday,Herrmann added that a police special unit happened to be in the area and was able to respond to the incident quickly.

Victims from Hong Kong

On Tuesday, Herrmann also told ZDF public television that two victims were in a critical condition. The four injured victims were a family from Hong Kong. Hong Kong's top official, Chief Executive Leung Chun-Ying, issued a statement condemning the attack and said representatives from the Hong Kong office in Berlin were visiting the victims in hospital. The "South China Morning Post" newspaper reported that the family included a father, mother, daughter and the daughter's boyfriend. Another family member, a son aged 17, was not hurt, the newspaper reported.

'We cannot guarantee 100 percent safety'

In light of the recent mass-casualty terror attacks in neighboring France and