The Soviet government tonight announced the ending of the Geneva strategic arms talks with the United States without providing any clues as to what had derailed agreement.

The official press agency Tass asserted that "as a result of a concrete and in-depth discussion . . . the positions of the two sides on a number of basic outstanding questions were brought closer together."

It said Moscow and Washington "expressed determination to complete thrashing out the remaining questions by using ordinary channels," meaning without more meetings at the foreign minister level.

Earlier today, Moscow Radio reported that "both sides have agreed to extend the meeting so as to resolve the remaining questions and prepare the conditions for signing the SALT agreement at a summit." The Moscow Radio dispatch suggests tht the Soviets may have been anticipating a successful conclusion to the latest round of bargaining and a summit meeting soon between Soviet President Leonid Brezhnev and President Carter.

Tass said Foreign Minister Andrei Gromyko and Secretary of State Cyrus Vance "also exchanged opinions on a number of other questions of Soviet-American relations and on certain international problems of mutual interest." These may well have included the U.S. Chinese agreement of last week to normalize relations after 30 years.