A German man who repeatedly drove into crowds and injured eight people in apparent intentional attacks against foreigners has been ordered kept in detention pending possible charges, police said Wednesday.

The attacks began shortly after midnight on Jan.1, first in Bottrop in western Germany and later in the nearby city of Essen. The 50-year-old suspect, who comes from Essen, is believed to have no previous police record.

The victims included a 46-year-old Syrian woman who suffered life-threatening injuries.

Police said a judge on Tuesday night ordered the suspect held in detention while the investigation on suspicion of attempted murder continues.

They say the suspect made anti-foreigner comments during his arrest and there were indications he had been treated for mental illness in the past.

The attacks came after four teenagers from Afghanistan, Syria and Iran were arrested on suspicion of bodily harm following assaults on passers-by near the railway station in the southeastern town of Amberg on Saturday. The four were apparently intoxicated and 12 people were hurt, in most cases slightly.

There was no indication of any link between the events, other than that both underlined tensions in Germany over migration.

German government spokeswoman Martina Fietz said Wednesday the government had learned "with dismay" of both the assaults and the attacks.

"There is no place in Germany for extremism, xenophobia and intolerance, no matter what side it comes from," she told reporters.

The Amberg incident prompted Interior Minister Horst Seehofer to tell the Bild daily that "if asylum-seekers carry out violent crimes, they must leave our country." He said, if necessary, laws should be changed to make that possible.