MOSCOW — The Soviet Union detonated an underground nuclear device Friday in its 16th nuclear test since abandoning a unilateral moratorium last February, the Tass news agency reported.
The test came as Soviet Foreign Minister Eduard A. Shevardnadze held talks in Washington that resulted in the superpowers reaching agreement in principle on a treaty banning U.S. and Soviet intermediate-range nuclear missiles.
As part of the negotiations, U.S. and Soviet spokesmen announced Thursday that the two sides would begin full-scale negotiations by Dec. 1 to end all nuclear weapons tests.
Both sides said effective verification would be a key to any agreement to ban nuclear testing.
Tass said the Friday blast at the Semipalatinsk test range in Soviet Central Asia had a yield of up to 20 kilotons. One kiloton is the equivalent of 1,000 tons of TNT.