A man dressed as Santa drugged a 15-year-old girl at a Berlin Christmas market over the weekend _ the latest such attack that has seen holiday revelers left either sickened or unconscious, police said Monday.

At about 10 p.m. Saturday the suspect approached the girl and her friend at Berlin's downtown Alexanderplatz Christmas market, offering both of them what he said was a shot of alcohol in a paper cup, police said.

One girl refused, but the other girl drank both of the shots. She soon started vomiting and had to be taken to the hospital, where she underwent a blood test, before being released.

Police said it appeared she had been slipped some type of a date rape drug, but released no further details, citing the ongoing investigation.

Eight other people at various Berlin Christmas markets have fallen prey to similar attacks _ usually with an unidentified man in regular clothes handing out single-shot bottles of alcohol, asking people to join him in celebrating the birth of his child.

Police say some of the victims _ mostly young women _ have lost consciousness and many have been briefly hospitalized. All have experienced dizziness and nausea.

It's not yet clear whether all the attacks are linked, or whether some may be copycat crimes, and police spokesman Ivo Habedank said authorities did not yet have a good description of the suspect.

"Intense investigations are ongoing," Habedank said.

Most recently, a 31-year-old woman who had read media reports of the attacks reported to police Sunday night that she and her friend, a 33-year-old man, had both fallen ill Dec. 7 after drinking small bottles of alcohol given to them at the Alexanderplatz Christmas market by a man saying he was celebrating becoming a first-time father.

She described the man as about 40-years-old and 5-foot 9-inches (180 centimeter) tall but no further details were released.

In Germany, Christmas markets are traditional outdoor holiday markets that are popular with residents and tourists alike throughout December, bringing together stands selling handicrafts, ornaments and small gifts along with a wide array of food and drink, including multiple varieties of hot mulled wine.