PARIS/DUBAI (Reuters) - Iran's supreme leader said on Monday he had personally rejected an offer from the United States for talks to fight Islamic State, an apparent blow to Washington's efforts to build a military coalition to fight militants in both Iraq and Syria.
World powers meeting in Paris on Monday gave public backing to military action to fight Islamic State fighters in Iraq. France sent jets on a reconnaissance mission to Iraq, a step toward becoming the first ally to join the U.S.-led air campaign there.
The United States launched an air strike against an Islamic State target southwest of Baghdad, the U.S. Central Command said on Monday night, expanding its campaign against the militant group that has seized parts of Iraq and Syria.
Iran, the principal ally of Islamic State's main foes in both Iraq and Syria, was not invited to the Paris meeting. The countries that did attend - while supporting action in Iraq - made no mention at all of Syria, where U.S. diplomats face a far tougher task building an alliance for action.
Washington has been trying to build a coalition to fight Islamic State since last week when President Barack Obama pledged to destroy the militant group on both sides of the Iraqi-Syrian border.
That means plunging into two civil wars in which nearly every country in the Middle East already has a stake. It also puts Washington on the same side as Tehran, its bitter enemy since the Islamic revolution of 1979.
In a rare direct intervention into diplomacy, Iran's supreme leader, Ayatollah Ali Khamenei, said Washington had reached out through the Iranian Embassy in Baghdad, requesting a meeting to discuss cooperation against Islamic State.
Khamenei said that some Iranian officials had welcomed the contacts, but he personally vetoed them.
"I saw no point in cooperating with a country whose hands are dirty and intentions murky," the Iranian leader said in quotes carried on state news agency IRNA. He accused Washington of "lying" by saying it had excluded Iran from its coalition, countering that it was Iran that had refused to participate.
U.S. Secretary of State John Kerry said Washington was "not cooperating with Iran" but declined to be drawn on whether it had reached out through the embassy in Baghdad for talks.
"I am not going to get into a back and forth," he said. "I don't think that's constructive, frankly."
Islamic State fighters have set off alarms across the Middle East since June when they swept across northern Iraq, seizing cities, slaughtering prisoners, proclaiming a caliphate to rule over all Muslims and ordering non-Sunnis to convert or die.
IS fighters, known for beheading their enemies or captives, raised the stakes for the West by cutting off the heads of two Americans and a Briton in videos posted on the Internet that showed the prisoners bound in orange jumpsuits.
French officials said they had hoped to invite Iran to Monday's conference, but Arab countries had blocked the move.
"We wanted a consensus among countries over Iran's attendance, but in the end it was more important to have certain Arab states than Iran," a French diplomat said.
Calling the decision regrettable, Iraqi Foreign Minister Ibrahim al-Jaafari said Baghdad had wanted Iran to attend.
Iran sponsors the governments of both Iraq and Syria and has been at the center of defenses against Islamic State in both countries. The United States reached out to Iran last year when secret talks led to a preliminary deal on nuclear issues.
Iran has occasionally played down its conflicts with the West since President Hassan Rouhani, a relative moderate, was elected last year. Khamenei's intervention, including his statement that some Iranian officials welcomed the U.S. overture, was a rare public acknowledgment of division but also a reminder that powerful interests in Iran oppose a wider thaw.
At Monday's international conference in Paris, the five U.N. Security Council permanent members, Turkey, European and Arab states and representatives of the EU, Arab League and United Nations all pledged to help Baghdad fight Islamic State.
"All participants underscored the urgent need to remove Daesh from the regions in which it has established itself in Iraq," said a statement after the talks. Daesh is an Arabic acronym for the group that now calls itself Islamic State.
"To that end, they committed to supporting the new Iraqi government in its fight against Daesh, by any means necessary, including appropriate military assistance...." it said.
Several Western and Arab officials said no concrete commitments were made and that talks on the different roles of those in the coalition would take place bilaterally and over the next 10 days at the United Nations General Assembly.
"This conference was like a mass. A big gathering where we listen to each other, but it's not where miracles happen," said another French diplomat. "It was a strong political message of support for Iraq and now we prepare to fight."
Foreign Minister Laurent Fabius said French aircraft would begin reconnaissance flights over Iraq. A French official said two Rafale fighters and a refueling aircraft had set off.
"The throat-slitters of Daesh - that's what I'm calling them - tell the whole world: 'Either you're with us or we kill you'. When one is faced with such a group there is no other attitude than to defend yourself," Fabius said at the end of the talks.
Iraqi President Fouad Massoum told Monday's conference he hoped the Paris meeting would bring a "quick response".
"Islamic State's doctrine is either you support us or kill us. It has committed massacres and genocidal crimes and ethnic purification," he told delegates.
Monday's conference was an important vote of confidence for the new Iraqi government formed last week, led by a member of Iraq's Shi'ite majority, Prime Minister Haider al-Abadi, and also including minority Sunnis and Kurds in important jobs.
Iraq's allies hope Abadi will prove a more consensual leader than his predecessor, Nuri al-Maliki, a Shi'ite whose policies alienated many Sunnis, and that the new government will win back support from Sunnis who had backed the Islamic State's revolt.
The broad international goodwill toward Abadi shown at Monday's conference means Washington will probably face little diplomatic pushback over plans for air strikes in Iraq.
Syria, however, is a much trickier case. In a three-year civil war, Islamic State has emerged as one of the most powerful Sunni groups battling against the government of President Bashar al-Assad, a member of a Shi'ite-derived sect.
Washington and its allies remain hostile to Assad, which means any bombing is likely to take place without permission of the Damascus government.
Senior U.S. officials said on Monday the Syrian military's air defenses would face retaliation if Damascus attempted to respond to U.S. air strikes expected against Islamic State targets in Syria..
The U.S. House of Representatives will begin debating legislation on Tuesday to give approval for arming and training rebels who oppose both Islamic State militants and Syria's government.
Russian Foreign Minister Sergei Lavrov told reporters in Paris that Moscow was already providing military assistance to both Iraq and Syria, suggesting Western countries were guilty of a double standard by helping Assad's foes.
"Terrorists can't be good or bad. We must be consistent and not involve our personal political projects, not prioritize them over the general goal of fighting terrorism."
U.S. officials said several Arab countries had offered to join air strikes against Islamic State, but declined to name them. Ten Arab states committed last week to a military coalition without specifying what action they would take.
Britain, Washington's main ally when it invaded Iraq in 2003, has yet to confirm it will take part in air strikes, despite the killing of British aid worker David Haines by Islamic State fighters this past week.
Obama will meet on Tuesday at the White House with retired Marine General John Allen, who is in charge of coordinating the activities of the coalition against Islamic State.
Additional reporting by John Irish, Marine Pennetier, Alexandria Sage and Nicholas Vinocur, and Missy Ryan, Steve Holland, Patricia Zengerle and David Lawder in Washington; Writing by Peter Graff; Editing by Peter Millership, Peter Cooney and Ken Wills