"The operation has been closely examined from the ecological point of view and approved by all the ministries concerned," the company's press service said.

The technology involved "has been used in the Caspian Sea and guarantees zero leakage," it said.

Lukoil was reacting to concerns voiced by Lithuanian ecology groups and published in the Finnish daily Hufvustadsbladet.

The groups warned that Lukoil was preparing to drill at a depth of barely 30 metres (100 feet) and just 20 kilometres (12 miles) off the coast of Lithuania's Curonian Spit, a natural site inscribed in the World Heritage List as an international Russian-Lithuanian cultural complex.

The effects of an oil spillage would be catastrophic and irreversible, ecologists warn.

Lukoil stressed that "all waste will be collected at the drilling site and transported to the coast to be treated there. None will go into the water. This is an avant-garde technology that has not been used in Russia before."

The oil will pass through an undersea pipeline before being transhipped into a double-hull tankers, the Lukoil press service said.

Extraction of the Baltic oil is expected to begin next year.

The deposits, discovered several decades ago, are believed to contain around 24 million tonnes of oil.

Plans to extract the oil during the 1980s were aborted after the Baltic republics, then preparing to break away from the Soviet Union, issued strong protests.

TERRA.WIRE