It was a tense two hour standoff in the Portuguese capital.
Uniformed police formed a barrier around the parliament building to keep out more than 10,000 protesters.
But these demonstrators were themselves police. Dozens of them pushed up against the police line but failed to break through.
These off-duty police officers and other security officials are angry about cuts to their pay, pensions and welfare benefits. The move is part of the government's cost-cutting austerity reforms to reduce spending.
(SOUNDBITE) (English) PRESIDENT OF THE NATIONAL POLICE UNION, ARMANDO FERREIRA, SAYING:
"And these cuts are very high, in a year it's nearly 5000 Euros less in the base salary of a police officer in Portugal and police officers, they are tired, and very, very angry with the government because the government is treating them as normal public servants and not as police officers."
The government agreed to the measures when Portugal took a $108 billion bail