U.S. President Barack Obama said on Wednesday he was confident the U.S.-led coalition can push back terrorism in Iraq, but Syria is a broader, more difficult long-term problem.
Earlier, Secretary of State John Kerry said the coalition has inflicted serious damage on the Islamic State of Iraq and Syria (ISIS), but the fight could last years.
The United States and its allies began air strikes in September after the Sunni militants made large territorial advances. The Iraqi army, Sunni tribal fighters and Kurdish forces have since recovered some ground from the group which in its Arabic acronym is known as Daesh.
“It is much harder now than when we started for Daesh to assemble forces in strength, to travel in convoys and to launch concerted attacks,” Kerry said at a meeting in Brussels of some 60 countries involved in the coalition.
“No large Daesh unit can move forward aggressively without worrying what will come down on it from the skies,” he added.
But he said the campaign would be a long one, saying: “Our commitment will be measured most likely in years.”
Kerry declined to comment on reports from officials in Washington that Iran - not part of the U.S.-led coalition, but a neighbor and ally of Iraq - had conducted air strikes.
“Nothing has changed in our fundamental policy of not coordinating our military activity, or any other activity, at this moment with Iranians. We are not doing that,” he told a news conference.
Kerry said he hoped countries in the region would take the lead in paying for reconstruction of parts of Iraq once they had been seized back from Islamic State control.
“There are a number of countries in the region that are talking about a...reconstruction fund,” he said.
Kerry said the United States had taken no decision to back a buffer zone along the Syria-Turkish border. The Wall Street Journal said this week a safe zone was a possible U.S. concession to Turkey in return for use of bases to launch attacks on Islamic State militants in Syria.
“There is a lot of discussion going on about the way we will go forward but it is premature to suggest at this moment of time that we are close to making a decision or moving forward with any form of a safe zone or a buffer zone,” Kerry said.
Meanwhile, French President Francois Hollande said France was ready “to step up actions” against Islamic State militants in Iraq and “carry them out with speed and efficiency.”
“We will continue to provide military support to Iraq, which is the victim of a large-scale terrorist attack,” Hollande said in a joint statement with visiting Iraqi Prime Minister Haider al-Abadi.
Abadi told the Brussels meeting his armed forces needed help with arms, ammunition and training, Croatian Foreign Minister Vesna Pusic told Reuters.
Iraq plans to ask NATO to help train its security forces, the military alliance said.
In a statement issued after the meeting, the anti-Islamic State coalition said some members had said that effective ground forces were needed to ultimately defeat the militants.