Police detain a supporter of anti-immigration right-wing movement PEGIDA (Patriotic Europeans Against the Islamisation of the West) during a protest march in reaction to mass assaults on women on New Year's Eve, in Cologne, Germany January 9, 2016. Picture taken January 9, 2016. REUTERS/Wolfgang Rattay

A group of Pakistanis and a Syrian were attacked in Cologne amid tensions over New Year’s Eve assaults in the city that have been blamed largely on foreigners, police said Monday.

Six Pakistani nationals were attacked Sunday by a group of around 20 people and two of them were briefly admitted to a hospital, police said. Also Sunday evening, a Syrian man was attacked by five people. He was injured but didn’t need treatment.

Police said they received tips Sunday afternoon about groups of people who would “seek provocation,” but were still investigating whether the subsequent attacks were racially motivated and whether there was any link to the New Year’s assaults.

Those assaults have stoked tensions over Germany’s open-door policy in the refugee crisis and prompted politicians to call for tougher laws against migrants who commit crimes.

Authorities and witnesses said the New Year’s Eve attackers were among a group of about 1,000 people described as predominantly Arab or North African who gathered at Cologne’s central train station. Some broke off into small groups and groped and robbed women, police said.

Cologne police say 516 criminal complaints have now been filed with them in connection to the New Year’s attacks. About 40 percent involve allegations of sexual offenses.

In a separate incident, police said Sunday two migrants — a Syrian and an Afghan — were arrested in northern Germany on suspicion of attacking and robbing a French man who was wearing a Jewish skullcap.

Police said the 49-year-old was in a waiting room at Puttgarden ferry port Saturday when the two men, saying “Jew” in Arabic, shoved him to the floor. Tstole a bag containing cash, a bank card, a train ticket and a cellphone.

The two men had been denied entry to Denmark the previous day because they lacked the correct papers and were waiting for a train to a refugee center.