A knife attack in the eastern German city of Dresden two weeks ago is being investigated as a terrorist attack, prosecutors said on Wednesday.

One tourist was killed and another one was seriously injured in the attack on October 4.

A 20-year-old Syrian man, who is believed to have an Islamist background, was arrested on Tuesday evening in connection with the attack, according to police and prosecutors.

Prosecutors believe the suspect has been in the country since 2015.

Justice Minister Christine Lambrecht said the case had been given the "highest priority" and had been taken over by federal prosecutors.

No motive for the attack has been established yet.

(With input from agencies)