Dutch police say an unknown number of people have been killed after twin shootings in Rotterdam.

A male attacker, 32, first opened fire at a home before setting the building alight, local media report.

He then made his way to the city's Erasmus Medical Center where he shot at least one other person.

Armed police teams later entered the building, and the suspect was arrested. A police briefing is expected shortly.

In a post on X, formerly known as Twitter, Rotterdam's police said the detained suspect was a city resident.

The police said there were no indications of a second gunman.

Earlier, staff were seen running out of the Erasmus Medical Center with patients, some of them on stretchers.

On two hospital windows taped papers were seen reading: "Room 32. We can't get out!"

Police said they were searching for further victims in the university hospital building, Dutch news agency ANP reported.