Soviets to Keep A-Test Ban Until March 31

The unilateral Soviet moratorium on nuclear weapons tests will remain in force at least until March 31 despite the United States’ weekend nuclear test, a government press agency said today.

Soviet leader Mikhail S. Gorbachev imposed a five-month ban on nuclear tests last Aug. 6, and in January extended it for three more months. He announced earlier this month that the moratorium would be extended beyond March until the United States conducted another test, which it did Saturday beneath the Nevada desert.

The Soviet press agency Novosti said the Soviet position on tests after March 31 depends on whether the United States continues its resistance to Kremlin calls for a joint test ban.

“The Soviet Union’s unilateral nuclear moratorium is due to end on March 31,” Novosti said. “If after its expiry the U.S.A. stand remains unchanged, a blow will be struck at people’s hopes for lasting peace, a blow that may prove irreparable.”

The Soviets have not said when or under what conditions they might resume nuclear testing after the March 31 expiration of the moratorium.

Joint Ban Rejected

Reagan Administration officials have rejected a joint nuclear test ban, saying it would be difficult to verify. Some officials also say that the Soviet Union is ahead of the United States in weapons testing and that a ban would hinder development of the so-called “Star Wars” space-based missile defense system.

Soviet media criticized the Reagan Administration for allowing Saturday’s test.