The British foreign secretary, Lord Carrington, formally presented the European Common Market's proposals for a negotiated settlement in Afghanistan to Soviet officials today, but the European initiative was immediately dismissed as "unrealistic."

Soviet Foreign Minister Andrei Gromyko added in a press conference after five hours of talks with Carrington that outsiders should "keep their hands off" internal Afghan developments. The stiff response made it clear that the Kremlin is unwavering in its military commitment to support the government in Kabul despite the diplomatic trouble its December 1979 intervention continues to bring.

Carrington said at the press conference that the Soviets objected to the proposal's failure to include participation of the Babrak Karmal government from the start of any negotiations. Saying he was "disappointed" but "not surprised," and determined to "continue the dialogue," he added, "the Soviet Union didn't accept the proposal I presented on behalf of the heads of government of the Ten [members of the European Community]. But nor did they say they rejected it. What they did was to describe it as unrelastic in its present form."

Carrington said he found the Soviet arguments unconvincing.

"They said the main problem was external intervention in the affairs of Afghanistan, but didn't include the Soviet Union among the intervenors. I said the Soviet intervention was the root of the problems, but our proposal was designed to deal with external intervention from any source . . . There are big differences between us, but a period of reflection on both sides is not a bad idea."

The two-stage EC plan would begin with a conference of the five permanent U.N. Security Council members, plus Afghanistan's neighbors, to work out guarantees for Afghan security as a nonaligned state.

The future form of government there would be determined at a follow-up conference of Afghan representatives and the convenors.Although Carrington called the Babrak government "unrepresentative," the Soviets insisted that it be included from the start.

The two ministers talked informally about Poland over lunch, the British said, but both sides declined to devulge either the substance of those conversations or of informal conversations on other matters, such as reduction of strategic missiles in Europe.