Four people died after a fire erupted at a hospital in the northern German town of Uelzen, local police said Friday, with the cause of the blaze still unknown. 

The fire, which occurred on Thursday night, also left "a double-digit number" of people injured, several of them seriously, according to a Lueneburg police spokesperson.

The fire broke out at 10:45 p.m. (2145 GMT), and when emergency services personnel arrived, flames were visible on the third floor as well as "a lot of smoke," police had said in an earlier statement.