Patna, Feb 15 (IANS) The Maoists blew up a portion of a government office building in Jamui district in Bihar early Monday during a 48-hour shutdown that they had called in the state, police said.

More than a dozen armed Maoist guerrillas attacked the Barhat block office in Jamui and blew up a portion of its building by using dynamite, a police official said.

"A portion of block office was badly damaged in the blast."

No casualties were reported as there was no one in the office building, the official said.

"Police and central para military forces have begun combing operation against the Maoists," the police official said.

The Maoists had called a two-day strike to protest against the killing of one of their top-ranking leaders in police encounter earlier this month.