The government intends to raise the retirement age for the armed forces starting 2018. At present soldiers can retire at 56. This rises to 63.
Today's demonstration by members of the armed forces is exceptional. The last such protest occurred in 2009.
Members of the armed forces are not allowed to strike, but chose the symbolic date of the King's Day holiday to press their grievances.
The protest started peacefully enough, but demonstrators tried to force their way past cheval de frise at the defence ministry.
Police responded with tear gas and water cannon. Several people were injured on both sides, but soon afterwards calm returned.