Israel has been offered a formula that could break an impasse over its refusal to accept a U.N. investigation into the killing of 20 Palestinians during a Jerusalem riot, diplomatic sources said Saturday.

The language, worked out with U.S. officials under the guidance of Israeli Ambassador Zalman Shoval, calls for United Nations Secretary General Javier Perez de Cuellar to send an envoy to Israel to discuss various Arab-Israeli issues, the sources said.But the emissary's role would be described only in general terms, steering away from any mention of the Oct. 8 riot, which began when Palestinians threw stones at Jewish worshipers and ended with Israeli police killing 20 Palestinians, the sources said.

Israel so far has rejected any U.N. investigation of the killings.

The formula has been forwarded to Israel, and it likely will be debated Sunday by the Israeli Cabinet, said the sources, who spoke only on condition of anonymity. But hardline members of the government are expected to oppose it, they added.

The formula also could run into opposition at the U.N. Security Council, which has adopted two resolutions calling for an investigation of the violence at a Jerusalem site revered by both Moslems and Jews.

In refusing an investigation, the Israeli government has cited years of U.N. hostility and concerns that such a probe would call into question Israeli sovereignty over Jerusalem.

Israel annexed the eastern part of Jerusalem, where the riot occurred, after capturing it from Jordan in a 1967 war. Most countries refuse to recognize the annexation.

The United States, which traditionally vetoes anti-Israel resolutions at the United Nations, voted twice in favor of an investigation.

Critics accused the administration of sacrificing its friendship with Israel to ensure the cohesion of the international coalition against Iraq.