Dozens of Libyan militiamen with trucks mounted with anti-aircraft guns have surrounded the Justice Ministry building in Tripoli in the third consecutive day of escalating tensions in the Libyan capital.

The militiamen sealed off the roads to the ministry with their trucks Tuesday and a standoff is underway.

On Sunday, about 200 armed men surrounded the Foreign Ministry. On Monday, armed men stormed the Interior Ministry and a state-owned television station.

The militias say they are rising up against former regime officials holding government posts. But many in Libya believe they seek to pressure the government of Prime Minister Ali Zidan for trying to disband them.

More than a year after Moammar Gadhafi's ouster in an eight-month civil war, Libya is struggling to build a unified army and police force.