Preliminary laboratory tests showed nothing to indicate that a nuclear-powered Soviet submarine released radiation after it caught fire and sank, Norwegian scientists said Sunday.

Early results of tests for radioactive contamination in air and surface water samples from the accident area showed no radiation from the sub, the government's Institute for Radiation Protection said."These tests checked to see if the Soviet sub released radiation on or near the surface of the ocean but cannot exclude the possibility of such a leak deeper in the ocean," said researcher Per Strand.

He said the tests will continue. They involve examining scrapings from Norwegian Orion reconnaissance aircraft that flew in the region immediately after the accident Friday and seawater collected near the site.

A Norwegian research vessel on Sunday will take new samples from deeper waters to assess the possibility of the sub having emitted radiation as it sank toward the seabed, Strand said.