RIO DE JANEIRO, Brazil (Reuters) -- Thieves tunneled into a bank in northeastern Brazil and stole $68 million, the biggest bank heist in the nation's history, police said on Monday.

"It's something you see in the movies. They dug a tunnel ... that goes underneath two (city) blocks. They've been digging for three months," police investigator Francisco Queiroga told Reuters by telephone.

The thieves broke into a branch of the central bank in the northeastern state of Ceara over the weekend and removed 156 million reais ($68 million).

The theft was not discovered until Monday morning because the bank was closed.

"The tunnel was dug right underneath the vault," Queiroga said. "We've never heard of so much money being stolen from a bank in Brazil."

Queiroga and the central bank said the tunnel was 200 meters (650 feet) long, but federal police who took over the case from local investigators said in a statement later it measured 80 meters (260 feet).

The tunnel, which started in a house rented by the gang, was reinforced with wood and plastic and had electric light.

Police said the thieves had perforated the concrete floor of the vault to get in, but motion sensors inside did not go off.

Federal police also said it was the biggest known heist in Brazil. They suspect that between six and 10 people did the job.

It exceeds the amount stolen by Britain's "Great Train Robber" Ronnie Biggs, who fled to Brazil and lived in the country for many years.

He and 11 other gang members robbed a Glasgow-to-London mail train in 1963 and made off with 2.6 million pounds -- some 30 million pounds ($53 million) in today's money.

that one made me laugh, its like one of those movies with matt damon!