Washington, D.C. ? Fishing nations led by Iceland and Russia have blocked United Nations negotiators from imposing a full-fledged ban against destructive bottom trawling on the high seas.

After weeks of talks in New York, a U.N. committee that oversees high seas fisheries failed to gain unanimous support this week for ending unregulated bottom trawling.

Fishing boats that drag giant nets along the sea floor can be as destructive as they are effective, wiping out creatures and habitats while scooping up everything in their path, according to a National Academy of Sciences report in 2002.

Iceland and Russia, along with China and South Korea, resisted a proposed ban that had the backing of President Bush and U.S. allies such as Britain, Norway, Australia and New Zealand.

Any one country can hold up the committee’s closed-door negotiations. Because of the impasse, the proposed ban probably won’t be considered at a plenary meeting of the 192-nation U.N. assembly next month in New York.