Two German boys have died after being buried by a dune slide on a beach in Denmark over the weekend, police said on Wednesday.

The children, aged nine and twelve, were digging a hole on a beach in northern Jutland on Sunday when the dune collapsed and buried them.

Police said health authorities reported the boys' deaths on Tuesday evening and considered the incident a “tragic accident.”

According to media reports, the boys, who were on holiday with their families from the Munich area, were trapped under the sand for up to 40 minutes during the rescue attempts.

In another incident on Sunday, another young boy was caught in a dune slide in southwest Jutland, but was quickly pulled out unharmed.

Following the incidents, Danish authorities urged the population to be cautious near the dune areas on the west coast, as the dunes had become unstable due to recent heavy rainfall.