WASHINGTON — As Iran awaits the latest report on its nuclear program from the International Atomic Energy Agency, the regime in Tehran is baring its teeth with preparations for a three-day show of its military might.

Even Iran’s immediate neighbors have been warned. Foreign Minister Manouchehr Mottaki fired off a salvo yesterday against Pakistan for harboring Baluchi separatists who claimed responsibility for blowing up a bus carrying Revolutionary Guard officials Wednesday and a subsequent blast in Zahedan, the capital of Iran’s Sistan-Baluchistan province.

Over the weekend, President Assad of Syria concluded a summit in Tehran that some in America’s counterintelligence community have dubbed a meeting of the “legion of doom.” “We should cooperate and work to make the public aware of the sinister aims of the United States and the Zionists,” Mr. Assad said Saturday after a meeting with President Ahmadinejad of Iran. Those “sinister aims,” the Syrian leader said, were to foment a civil war between Sunni and Shiite Muslims.

The developments in Tehran do not bode well for Washington’s plan to rally a bloc of allied Sunni-majority regimes in the Middle East to counter Shiite Iran’s regional ambitions and pry Syria from its alliance with Iran.

Senior American officers have accused the Iranian Revolutionary Guard’s elite Quds Force of arming insurgents in Iraq to attack American soldiers; yesterday, the 200,000-strong guard prepared for Iran’s war games.

The country’s state-run news service quoted the guard’s ground forces commander, Mohammad Reza Zahedi, as saying, “The message of this maneuver shows the whole Iranian nation’s readiness for defending their sacred country.”

That message was in keeping with a statement on Sunday from the Iranian supreme leader, Ayatollah Ali Khamenei, who declared that in any conflict, “America will lose.”

The brief tension between Pakistan and Iran ended later yesterday, just hours after it began, with both countries agreeing to take new steps to counter the threat of the Jundallah Organization of Iran, the Baluchi separatist group that has taken credit for two attacks in Iran since last week. A spokeswoman for the Pakistani Foreign Ministry, Tasnim Aslam, said yesterday that her country does not support the “terrorists.”

An American counterterrorism official said he doubted that Islamabad would have any official dealings with the Jundallah Organization of Iran, although Pakistan’s security services do support Kashmiri separatists in India.

“It’s a bizarre situation. This group is interested less in separatism than making money on the drug trade. The Pakistani government is so weak now that they would not be trying to pick a fight with Iran anyway,” the official, who requested anonymity, said.

Iran’s influence in the region has been of particular concern to Israel, which considers the Islamic Republic the main sponsor of the Hamas government in Gaza.

On that score, Secretary of State Rice came up short yesterday in her efforts to launch final status talks between Israel and the Palestinian Arab president, Mahmoud Abbas, whose Fatah Party until recently was at war with Hamas. Earlier this month, Mr. Abbas signed an agreement in Mecca with Hamas, which won control of the Palestinian Authority ministries after winning legislative elections in January 2006. The agreement has worried both American and Israeli officials, as under its terms Hamas does not explicitly have to recognize a two-state solution or Israel’s right to exist.

Yesterday, Ms. Rice received few concrete commitments toward a future summit with Mr. Abbas and Prime Minister Olmert. The two parties said in a statement: “The President and the Prime Minister agreed that they would meet together again soon. They reiterated their desire for American participation and leadership in facilitating efforts to overcome obstacles, rally regional and international support, and move forward toward peace.”