A gang of crafty scrap metal thieves dismantled and decamped with a 500-tonne defunct iron bridge in eastern India, police said Saturday, pulling off the unlikely heist by pretending to be irrigation officials.

The robbing of the bridge was reported Wednesday in the state ofBihar, one of the poorest in the country.

Police officer Subhash Kumar told AFP the thieves came in the guise of government irrigation officials.

They brought bulldozers and gas cutters and tore apart the structure before escaping with the booty over two days, Kumar said.

“They took away the scrap in a heavy vehicle,” he said.

The thieves had been chipping away at the 50-year-old structure — built over a water canal — ever since another bridge nearby was opened to the public five years ago.

Police launched an investigation into the bizarre incident on Thursday but no arrests have been made so far.(AFP)