Women say they were drugged at summer gathering of Germany's ruling party

Nine women have reported they were drugged by an unknown substance after attending the annual summer party of Germany's Social Democratic Party (SPD) -- whose Chancellor Olaf Scholz is a member -- last week.

According to a police report, a 21-year-old woman started to feel "unwell and dizzy" Wednesday evening after eating and drinking at the party. Being unable to remember the previous day's events, the woman had herself examined in hospital and filed a complaint with Berlin police.

Police told CNN on Monday that a toxic substance was found in the patient's blood explaining her symptoms and amnesia.

"The task forces initiated an investigation procedure because of dangerous bodily injury against unknown and ordered a blood withdrawal, which was still accomplished in the hospital, for the purpose of toxicological analysis," the police report says. Four additional cases were reported to the Criminal Investigation Department. An SPD spokesman told CNN that the reported cases had increased to nine.

"We encourage the victims who were attacked to come forward and press charges," the SPD spokesman told CNN on Monday. "Since the beginning, we have supported the police to the best of our ability to ensure that this terrible incident is resolved," he added.

The director of the SPD parliamentary group, Katja Mast, tweeted on Saturday: "We are all appalled by this unbelievable event and will do everything in our power to clear it up." She also advised all those affected to report the matter to the police.

About 1,000 guests attended the annual summer party which took place next to the Chancellery in Berlin. German Chancellor Scholz as a member of the party was among the guests according to the SPD spokesman. The party was about half the usual size due to Covid precautions and consisted mainly of internal SPD participants, a party spokeswoman told CNN.