A debate in the Dutch parliament was halted after a man jumped from the elevated public gallery, police say.
The man, who reportedly survived the incident, was identified as an activist who had campaigned for the legalisation of marijuana, local media report.
Eyewitnesses said he appeared agitated before he tied something to a rail and leapt from a height of several metres in an apparent attempt to kill himself.
A video recorded in parliament shows the shocked reaction of lawmakers.
Police said the 65-year-old man received medical treatment for his injuries, although it is not yet clear how serious they are.
Dutch newspaper De Telegraaf reported that he had camped outside parliament in The Hague for several weeks in a demonstration for the legalisation of hashish and marijuana.
Cannabis is technically illegal in the Netherlands, though police do not prosecute people for possession or sale of small amounts.
Images shared on social media show the man receiving first aid on a desk within the building and later being removed on a stretcher.
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