The commission's inquiry concluded that both possible pipeline routes through an ecologically-sensitive region of Siberia are equally undesirable, Yankov told a meeting of ecologists in the Siberian city of Irkutsk.

The proposed oil pipeline to China, a 2,400-kilometre (1,500 mile) cross-border line linking Siberian oilfields in Angarsk to the Chinese city of Daqing, is backed by Russia's largest oil producer Yukos.

Yukos is lobbying for a route through the Tunka national park that would curve around the southern end of Lake Baikal, a vast inland lake which contains about one-fifth of the world's freshwater reserves.

A second proposed route would follow the path of the Baikur-Amur railway, which crosses the northern end of Lake Baikal, listed as a world heritage site by UNESCO.

"In the first case this runs counter to Russia's laws on nature conservation, in the second this is impossible since the consequences of a possible burst in the pipeline could not be promptly eliminated," the deputy minister said.

However, Yankov said this did not mean that the pipeline project -- which is furiously opposed by local green campaigners -- should be abandoned altogether.

During a visit by Chinese President Hu Jintao in May, Yukos and China National Petroleum Corporation (CNPC) signed a 25-year deal to supply oil through a pipeline to China which was considered a clear sign that Russia wanted to press ahead with the scheme.

China has offered to help finance the construction of the pipeline to squash a rival project championed by Japan, a 4,000-kilometre (2,500-mile) oil pipeline from Angarsk along the Pacific coast to Nakhodka, on the Sea of Japan.

TERRA.WIRE