Several thousand Belgian military personnel on Tuesday marched in the streets of Brussels over a rise in the pension age, at times clashing with police.

Authorities said 8,500 off-duty soldiers protested in the historic centre of the city, with riot police firing water cannon after receiving projectiles of smoke bombs and firecrackers from the protestors.

For the past year, Belgian military personnel have worked around the clock guarding government and EU buildings with Brussels under high alert after the deadly terror attacks in Paris in November 2015 and Brussels last March.

The government last month announced an increase in the pension age for soldiers to at least 63 years old from the current 56.

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