BERLIN, Jan. 11 -- People of Pakistani and Syrian nationalities have been attacked by several unknown violent people in groups in the western German city of Cologne, German media reported on Monday.

According to German media Spiegel Online, a group of about 20 people attacked six Pakistanis on Sunday evening around 18:40 o'clock local time.

Two of those attacked were then brought to hospital due to injuries, but have been released by now.

About 20 minutes later, five people attacked a 39-year-old Syrian, who got slightly injured.

The police are reportedly investigating both cases for grievous bodily harm. However it is still unclear whether there is a connection between the incidents.

In the afternoon the police had received information on "groups of people,who would deliberately seek provocations", it said in the statement on Sunday evening.

The police have been out in downtown "with strong presence" on duty, said the report.

According to a survey by polling institute Forsa, the majority of Germans sees foreigners not more negatively than previously after the sexual attacks and theft on New Year's Eve in Cologne.

While 60 percent of respondents said their personal assessment of foreigners had not become critical, 37 percent, however, said they had received after the incidents a more critical and more negative assessment of foreigners.

On New Year's Eve, a group of 1,000 men have surrounded, harassed and robbed, especially women in Cologne. According to eyewitnesses and victims, the perpetrators were from the Arabic or North African region judging from their appearance.

So far, German police have identified a total of 31 suspects most of whom were asylum seekers.

German Chancellor Angela Merkelhas announced that her party has decided to take tougher actions against criminal refugees.