ATHENS, Greece — Police clashed with scores of protesting shipyard workers Thursday after they forced their way into the grounds of Greece's Defense Ministry in Athens.

Riot police were called in to force back the protesters after the leader of the country's armed forces, Gen. Michalis Costarakos, failed to persuade them to end an attempted blockage of the entrance to the building, about 5 kilometers (3 miles) north of central Athens.

Workers from the Skaramanga Shipyards, which deals mainly with military contacts, say they have not been paid in months.

Greece has been gripped by a severe financial crisis since late 2009, and waves of spending cuts and tax hikes have led to frequent strikes and demonstrations.

The country's coalition government is currently preparing a major new austerity package demanded by rescue creditors.