The Soviet Union announced a unilateral four-month nuclear test moratorium Saturday, apparently because of pressure from local governments and residents who live near test sites.

Deputy Prime Minister Igor Belousov told the Soviet Parliament Saturday the moratorium would last for "forthcoming four months of 1991."The last announced Soviet nuclear test occurred at the Novaya Zemlya island test site in the Bering Sea near the Arctic Circle. That test, on Oct. 24, was the Soviet Union's first nuclear explosion for more than a year.

Belousov said the decision to stop testing for four months was "the result of the desire of the Soviet leadership to find an acceptable solution to socio-economic problems dealing with the conducting of tests," the official Tass news agency said.

Protests by local residents shut down the Soviet Union's primary test site near Semipalatinsk in central Asia last year, and the secondary site at Novaya Zemlya was the subject of international protests.

A ship from the environmental movement Greenpeace was boarded, detained and expelled from Soviet waters before the test in October because it landed people on one of the islands to protest nuclear testing in the Arctic.

The October test followed warnings by a top official in the Soviet atomic energy ministry that national security was jeopardized by a Soviet moratorium while the United States continued with a nuclear testing program.

The Soviet Union has called for a complete international ban on all nuclear tests, but says it needs to keep updating its weapons as long as others are doing so.