Grand Ayatollah Ali al-Sistani, Iraq's most influential Shiite leader, never meets with American officials. But when Iranian Foreign Minister Kamal Kharrazi arrived in Iraq this week, the revered Iranian-born cleric threw open his doors.
Their meeting revealed the warmth that met the foreign minister during his three-day visit, which sometimes felt more like a family reunion than a meeting of leaders of nations that fought throughout the 1980s, at the cost of 1 million dead and wounded. The trip that ended Thursday also underscored a US policy dilemma in Iraq.
"You've got two different trajectories, and I don't think the Americans have come to this realization," says Karim Sadjadpour, an Iran analyst with the Brussels-based International Crisis Group, contacted in Tehran. "The Americans have hard power in Iraq, but the Iranians have soft power, and they are able to do things. It is a much more subtle influence than the Americans."
Preaching the merits of stability and democracy for Iraq - and trying to dispel accusations from the US and previous interim Iraqi officials of interfering in Iraqi affairs - Mr. Kharrazi staked Iran's claim as Iraq's neighbor of greatest influence.
US Secretary of State Condoleezza Rice made a surprise visit to Iraq two days earlier. But Iraq's new government, formed on April 28, also has very close ties to Iran, often developed with Iraq's new leaders during years of exile when the Islamic Republic supported their struggle against Saddam Hussein.
"For US policy, it's going to be difficult to forge a strong alliance with Iraq, while at the same time antagonizing Iran," says Mr. Sadjadpour.
Senior US officials in the past have made clear their interest in pursuing regime change in Iran, and the US government considers Iran a state sponsor of terrorism. President Bush lists Iran as part of an "axis of evil."
But Iran shares an 800-mile border with Iraq, and the new government is run by Shiites who share a religious affinity with Iran, and constitute more than 60 percent of Iraq's population. Kharrazi is the first senior official from any of Iraq's six neighbors to visit the new government.
Senior US officials now play down concerns about Iran's role in Iraq, especially compared to that of Syria. Despite close ties with Iran, senior Iraqi officials "are Iraqis first and foremost," Deputy Secretary of State Robert Zoellick told journalists in Baghdad Thursday. "There is undoubtedly influence ... [but] what Iraq is doing is urging all its neighbors to be supportive."
After Mr. Hussein's fall, interim Iraqi leaders accused Iran of opening its borders to militants crossing into Iraq and supporting the insurgency. Analysts say that in the aftermath of the 2003 US invasion, Iran believed that it might be the US's next target, and so set up networks that could apply pressure in Iraq, if a decision was made to do so.
Iran analysts described Tehran's aim as "managed chaos," a tricky balancing act that would keep US forces and officials tied down in Iraq, but not spark the kind of breakdown that would threaten Iran. That undeclared policy seems to have shifted during the Iraq election period last January, which brought the current Iran-friendly government to power.
"We will not allow terrorists to use our lands to access Iraq," Kharrazi told his hosts. "We will watch our borders and will arrest infiltrators, because securing Iraq is securing [Iran].
"Had the Islamic Republic of Iran exploited the situation in Iraq to interfere in Iraq's affairs and allow terrorists to enter Iraq from Iran," Kharrazi added, "the situation in Iraq would have been much worse."
While the military is focusing now on rebels streaming in from Syria, Iraq's foreign minister Hoshyar Zebari said that "infiltrations occur [from Iran] but we cannot say that these operations take place with the approval of the [Iranian] government."
Mr. Zebari added: "We are sure the Islamic Republic does not want Al Qaeda and Abu Musab al-Zarqawi on our lands."
Part of Kharrazi's message appeared designed for the US, which has been pushing to have Iran brought before the UN Security Council to answer charges that Tehran is using its nuclear-power program as a cover to build nuclear weapons.
Kharrazi made clear that the US would "eventually withdraw" from Iraq, but that Iran, as Iraq's neighbor, would always "live with the Iraqis."
"I'm not sure how much of the [Iran-Iraq warmth] is love and real friendliness," says Ali Ansari, an Iran expert at St. Andrews University in Scotland. "The Iranians are making the most of it, reminding the Americans and Europeans that if things get hot on the nuclear issue, that Iran has a big influence in Iraq."
In an interview with Reuters, Iranian Presidential front-runner Ali Akbar Hashemi Rafsanjani Thursday said that Iran "cannot ignore" the US, and that Iran would "feel that America has given up its hostile policies" if the US "begin[s] to adopt positive behavior rather than doing evil."
But how great is Iran's influence with Iraq's leadership?
Iraqi Prime Minister Ibrahim al-Jaafari for years led an anti-Hussein group in Iran. In the early 1980s, the intelligence services of Ayatollah Ruhollah Khomeini - leader of Iran's 1979 Islamic revolution - created the Supreme Council for the Islamic Revolution in Iraq (SCIRI) and its military wing, the Badr Brigades, from which many of Iraq's top leaders now come.
On the Kurdish side, Iran has had the closest ties with the Patriotic Union of Kurdistan lead by Jalal Talabani, Iraq's new president. In 1996, when Iraqi forces launched an offensive into the Kurdish north, this correspondent met Mr. Talabani in northern Iraq, just strides away from the Iranian border.
Parallel anti-Hussein efforts were covertly funded and supported by the US, most notably with Deputy Prime Minister Ahmad Chalabi (who also has close Iran ties, and has been accused of giving US intelligence to Iran) and former Prime Minister Ayad Allawi.
Last week, during a visit to Iran, Talabani declared that it "feels good to be home."
While supporting the new Iraqi government, Tehran is torn by internal debate as it weighs the risks of "managed chaos" - and the seriousness of continuing US rhetoric against the Islamic regime - while recognizing that the "best way to get the Americans out of Iraq is to let it reach a certain level of stability," says the ICG's Sadjadpour.
"When Iran has a friend in power [in Iraq], they want to see that government succeed. And when Iran wants to flex its muscles in Iraq, it can," says Sadjadpour. "The danger is if there is heightened tension between the US and Iran. The battlefield for that will be in Iraq."