Defending their pensions from the threat of ever-deepening austerity cuts, as many as ten thousand off-duty police officers and state security agents in Portugal found themselves on the other side of the barricades Thursday night as they faced down their on-duty colleagues in riot control gear.

With a march through Lisbon that ended at the steps of parliament, the angry police and security union members broke through security fences, and even briefly occupied the entrance to Parliament before the night was over.

The proposed cuts in public pensions are being demanded by the nation's creditors in exchange for a government bailout package received in 2011.

As Agence France-Presse reports:

Thousands of Portuguese police officers, paramilitary police and other security officers took to the streets of the capital to protest the government's latest austerity measures.

Police in plain clothes massed outside parliament, where they broke through a security cordon to briefly occupy the steps leading up to the building.

During an earlier march, they had called for the government to resign, carrying a banner that read "For professional dignity and people's security."

Unions said the rally was the biggest ever organised by the country's police, and warned that budget cuts planned for next year would "destabilise the work of the police" and "deteriorate public security."

Media reports estimated the number of demonstrators at between 8,000 and 10,000.

"I've been with the police for eight years and never got promoted or a pay rise, even though I have a family now and more responsibilities," complained protester Manuel Ribas, 32.

"Next year, they will take another 100 euros [$135] out of my gross salary, which will leave me with 900 euros a month, just as if I had just left the police academy."

Following the raucous protest, the police superintendent of the nation's police Paulo Gomes tendered his resignation

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