CAIRO, Egypt – A Hamas leader visiting Tehran yesterday threatened to launch a new wave of terror in Israel and break an uneasy cease-fire – if the Jewish state attacks Iran’s nuclear facilities.

Hamas’s politburo chief, Khaled Mishal, made the threats yesterday after meeting with top Iranian security officials and Iran’s supreme leader, Ayatollah Ali Khamenei. The meetings between the Iranians and Mr. Mishal further prove Iran’s expanding relationship with the Sunni Arab group, which is planning to put forth candidates for January’s parliamentary elections in the Palestinian territories.

In the last month, Israel has grown impatient with the failure of the International Atomic Energy Agency to refer Iran to the U.N. Security Council for alleged violations of the Nuclear Nonproliferation Treaty, an agreement to which Israel is not a party. Last week the IAEA’s director-general, Mohammed ElBaradei, warned that Iran will be far closer to building a nuclear bomb if it continues to enrich the uranium it earlier this year promised Britain, France, and Germany it would not. Complicating matters, Iran’s president, Mahmoud Ahmadinejad, has escalated his war of words with Israel, claiming this week that the Holocaust was a myth and suggesting Israel relocate to Europe or America.

The prospect of Israel unilaterally bombing Iran’s nuclear facilities looks to be remote. This week Israeli officials dismissed a report that their country planned to bomb Iran in March. But a Likud politician, Benjamin Netanyahu earlier this month told reporters that if he were to become prime minister following elections scheduled for March, he would follow in the footsteps of a former prime minister, Menachem Begin, who bombed Iraq’s nuclear facilities in Osirak in 1981.

Mr. Mishal is based in Damascus and heads the politburo for Hamas, an organization that has been at war with Israel since its inception in the early 1980s. In 1997, the Mossad attempted to poison Mr. Mishal in Amman, Jordan, but the operation ran afoul, and the operatives dispatched to kill the Hamas leader were sent to jail and not released until Mr. Mishal received an antidote.

The Palestinian Authority’s leader, Mahmoud Abbas, has held firm in his pledge to allow Hamas to participate in parliamentary elections scheduled for January despite repeated requests from the Israelis to disarm the group. In America, the House is now considering a resolution says if Hamas participates in the new government and does not recognize Israel or disarm, it would “undermine the continued ability of the United States to provide financial assistance and conduct normal relations the Palestinian Authority.”

On Tuesday, the Kuwaiti News Agency quoted Iran’s supreme leader as saying negotiations with the Israelis are fruitless and that “the increase of pressure” and resistance were the surest path to victory.