United Nations Security Council called for possible punishment, saying the Iranians had given no sign they would bargain in earnest over their disputed nuclear program.

The move amounted to calling Iran’s bluff. Diplomats said recent meetings with Iran’s nuclear negotiator have gone nowhere and it was clear Tehran hoped to play for time or exploit potential divisions among the six powers that have offered new talks.

The United States and other nations wanted Iran to say by Wednesday whether it would meet terms to begin negotiations on a package of economic and energy incentives in exchange for at least a short-term end to Tehran’s program to enrich uranium.The Security Council’s permanent members said Iranian leaders had had long enough to respond.

“The Iranians have given no indication at all that they are ready to engage seriously on the substance of our proposals,” French Foreign Minister Philippe Douste-Blazy said on behalf of the United States, France, Britain, Russia and China, the five permanent Security Council members, and Germany.

Though Russia and China signed on to the statement, the two traditional commercial partners of Iran previously have opposed imposition of the toughest of sanctions.

Russian Foreign Minister Sergey Lavrov expressed his disappointment with Iran for not responding to the proposals. In a veiled warning that Russia could soften its opposition to sanctions, Lavrov said that if Tehran does not agree to return to negotiations “the Security Council will consider steps appropriate to the situation,” the ITAR-Tass news agency reported.

If Iran agrees to the group’s terms for negotiations, it would mean the first high-level face-to-face talks between the United States and Iran after more than a quarter century of estrangement.