WASHINGTON (AFP) - US President Barack Obama on Tuesday expressed grave concern over the plight of the Syrian town of Kobane under attack by ISIS (Islamic State in Iraq and Syria) and said a US-led coalition would keep up bombing raids there and in western Iraq.

"We're deeply concerned about the situation in and around the Syrian town of Kobane," Obama said after meeting commanders from countries in the coalition fighting the ISIS group.

The US leader said they were "also focused on the fighting that is taking place in Iraq's Anbar province".

The US president, sitting next to his national security adviser Susan Rice and the US military's top officer, General Martin Dempsey, said the US government was "also focused on the fighting that is taking place in Iraq's Anbar province".

The battles in Anbar province and Kobane illustrated the threat posed by the ISIS group in both Iraq and Syria and "coalition air strikes will continue in both these areas", he said.

Obama said there had been some "important successes" in the campaign against ISIS militants, citing the successful bid to retake and hold Mosul dam in Iraq.

The coalition chiefs agreed that "this is going to be a long term campaign", he said.

"There are going to be periods of progress and setbacks," he said.

But Obama added: "We are united in our goal." The effort to defeat ISIS was not merely a military operation and the campaign would require tackling the group's extremist ideology and its funding sources, Obama said.

The coalition would need to communicate an "alternative vision to those attracted" to the ISIS group, he said.