The Soviet Union today condemned the U.S. House of Representatives' approval last week of aid to Nicaraguan rebels, calling it "a new and extremely dangerous step" that will affect U.S.-Soviet relations and the international situation.

Last Wednesday the House approved a $100 million package of nonlethal and military aid to Nicaraguan counterrevolutionaries, known as contras, who are fighting the country's leftist government.

A statement released by the Soviet news agency Tass this evening said, "That action constitutes a most flagrant breach of international law, of the United Nations Charter and of the norms of civilized conduct of states.

"A new and extremely dangerous step has been taken to sharpen tension in Central America and to escalate the undeclared war which the United States has conducted against the region's peoples for a number of years now," Tass said.

The statement charged Washington with broadening "the material base for unleashing a large-scale armed conflict in Central America, in which many countries may get involved. Such a development of events is fraught with ruinous consequences not only for Central America," the statement continued. "It will inevitably affect the general situation in the world and will not fail to tell on Soviet-U.S. relations."

Moscow charged "U.S.-controlled" bands in Nicaragua with "state terrorism" and preventing "normalization of relations between Central American countries, to provoke and stir up conflicts between them."

The issue of U.S. involvement in Nicaragua arose in talks on Central America between U.S. and Soviet officials here last month, according to Moscow-based U.S. diplomats. "The differing viewpoints between the two sides on the issue were made quite clear," a western diplomat familiar with the talks said.