A man armed with a machine gun opened fire in a crowded shopping mall on Saturday, killing six people and wounding 15, then committed suicide, officials and witnesses said.

Children were among the casualties, but authorities were not prepared to say whether they were among the dead or the injured, or both, due to privacy considerations, said Mayor Bas Eenhoorn. Three of the wounded were hospitalized in critical condition.

After the rampage, the attacker shot himself in the head at the Ridderhof mall in Alphen aan den Rijn, a suburb 19 miles (30 kilometers) southwest of Amsterdam.

"It's too terrible for words, a shock for us all," said Eenhoorn.

The gunman was identified under Dutch privacy laws as 24-year-old Tristan van der V., and it was "all but certain" he acted alone, District Attorney Kitty Nooy said. She said he was a native Dutchman from Alphen who had previous run-ins with the law, including an illegal weapons possession charge that was dropped. He had a gun license, Nooy said.