City authorities in Moscow have halted plans for a US$1.2bn road tunnel that forms part of the Russian capital’s third ring road. Instead, officials have set up a special commission headed by the city’s construction chief, Vladimir Resin, to consider alternatives to the 2.15km long tunnel which would have been built under the landmark Lefortovo Park.

Among the options to be considered are a surface level road and a bridge, while the tunnel will also be reassessed to see if a cheaper underground alternative could be built.

A decision should be made by the end of September.

When the tunnel project was awarded last year to Russian construction company Organizator the scheme carried a $1.2bn price tag. Boris Nikolsky, a deputy mayor, said Organizator now estimates the cost at less than $900M.

"We calculated that the underground variant will cost around $900M," Nikolsky said.

Organizator has already spent $200M on preliminary work, company director Gennady Muravin said. But Mr Nikolsky said Organizator would be paid for work carried out so far. "That money will be reimbursed according to the law. Whatever version for the road is chosen, its work will be incorporated in the project," Mr Nikolsky said.

City officials initially chose the tunnel option after protests by conservationists who wanted to protect the park. The tunnel would have been one of the most expensive projects ever carried out by Moscow city council.

The scheme forms part of the third ring road, portions of which have been under construction since 1984, which links the Garden ring road and the outer ring road in an effort to ease traffic congestion in central Moscow.