BERLIN — A seven-month-old infant has died after being bitten in the head by the family's dog in southern Germany, police said Tuesday.

Police in Hesse state said it's unclear why the dog attacked the boy. The dog was taken to an animal shelter, where it was described as aggressive.

The 23-year-old father called emergency services immediately after the attack Monday, police said. The boy was taken to a hospital where his condition was initially stable, but he died in the evening.

The incident in Bad Koenig, about 45 kilometers (28 miles) southeast of Frankfurt, took place almost a week after two people were killed by a dog in northern Germany.

A 52-year-old woman and her 27-year-old son were killed by a Staffordshire terrier they owned on April 3 in Hannover.

Hesse police said the breed of the dog in the latest attack was unclear, but it appeared to be a mix including Staffordshire terrier features.

Germany's 16 states each have different rules for keeping certain dog breeds, though many require a special permit if people want to own pitbull terriers, bull terriers or Staffordshire bullterriers.

According to Germany's Federal Statistical Office, 64 people were killed by dogs in the country between 1998 and 2015.