Four people were seriously wounded in two knife attacks in one district of Vienna on Wednesday evening but any motive or connection between the assaults was unclear, a police spokesman said.

The stabbings ¡ª the first of which took place at 7:45 p.m. (1845 GMT), occurred in Vienna¡¯s Second District, which includes the famous Prater park as well as the Praterstern transport hub. It also houses much of Vienna¡¯s small Jewish community.

¡°A man attacked a family ¡ª a father, a mother and their 17-year-old daughter ¡ª with a knife. The three people were seriously injured and their lives are in danger,¡± the spokesman said.

¡°And half an hour later there was another attack ... at Praterstern and here a person was also seriously injured and their life is in danger. We do not know to what extent there is a connection here and any motive remains unclear,¡± he said.

Asked what was known about an assailant, he added: ¡°Absolutely nothing. We know we are looking for a man.¡±

Vienna has not experienced deadly attacks by Islamist militants like the ones that have struck Paris, Berlin and Brussels since 2015.