US-led aircraft will continue bombing near the Syrian town of Kobane and in western Iraq, President Barack Obama said Tuesday after talks with military leaders from an international coalition fighting the Islamic State group.

Obama voiced grave concern over the plight of Kobane but warned that the campaign would be a "long-term" struggle.

"Obviously at this point we're also focused on the fighting that is taking place in Iraq's Anbar province, and we're deeply concerned about the situation in and around the Syrian town of Kobane," Obama told reporters following his meeting with coalition military officers.

He said the battles in Anbar and Kobane underscored the threat IS posed in both Iraq and Syria, and "coalition air strikes will continue in both these areas."

Flanked by top brass from more than 20 countries, Obama cited "important successes" in the two-month-old campaign.

He pointed to a successful bid to retake Mosul dam in Iraq and halting the IS group's advance on Erbil.

He also hailed the coalition for having saved "many civilians from massacre" on Mount Sinjar, and destroying IS targets across Iraq and Syria.

But despite daily bombing raids in Iraq since August 8 and in Syria since September 23, IS jihadists have continued to advance.

The Sunni extremists are now threatening to seize the whole of Anbar province in Iraq and a long stretch of territory along Syria's border with Turkey.

The US strategy has come in for sharp criticism but Obama appealed for patience.

He said coalition commanders agreed there would be no rapid victory and were committed to a united front against IS militants.

"One of the things that has emerged from the discussions... is that this is going to be a long-term campaign," he said.

"There are not quick fixes involved. We're still at the early stages. As with any military effort, there will be days of progress and there are going to be periods of setback, but our coalition is united behind this long-term effort."

The US military's top-ranking officer, General Martin Dempsey, hosted the talks at Andrews Air Force base outside Washington -- the first gathering of top brass from so many nations since the coalition against the Islamic State group was formed in September.

Among those attending the meeting were officers from all five Arab states taking part in the Syria air campaign.

Countries taking part in the meeting were:Australia, Bahrain, Belgium, Britain, Canada, Denmark, Egypt, France, Germany, Iraq, Italy, Jordan, Kuwait, Lebanon, the Netherlands, New Zealand, Qatar, Saudi Arabia, Spain, Turkey, the United Arab Emirates and the United States.