WASHINGTON — The White House said Sunday it will find countries willing to send combat troops to fight Islamic extremists in Syria and Iraq, but it’s too early to identify them.

White House chief of staff Denis McDonough signaled that the State Department in coming days will name allies that will pledge ground troops to fight the Islamic State group, something the United States does not plan to do. Meantime, McDonough said, U.S. personnel will train and equip Iraqi forces and Syrian rebels to combat the extremist group, also known as ISIS and ISIL.

President Barack Obama announced Wednesday that the United States will ramp up airstrikes and try to build an international coalition to degrade and eventually destroy the group. The group released a video late Saturday showing a militant beheading a British aid worker. It was similar to recent beheadings of two American journalists.

Facing strong public opposition to sending U.S. troops back into the Middle East, Obama said he doesn’t plan to do so. But he said ground troops of some form are essential, a point McDonough was asked about on several talk shows Sunday.

McDonough repeatedly declined to name any nations willing to provide ground forces, and he was cautious in suggesting what might develop.

On NBC’s “Meet the Press,” McDonough said Secretary of State John Kerry “over the coming days” will discuss whether any allied nation has pledged ground troops. “And what he has said is that others have suggested that they’re willing to do that,” McDonough said.

Pressed again on possible pledges of combat troops, McDonough seemed slightly less hesitant. “You will hear from Secretary Kerry that countries are saying that they’re ready to do that,” he said.

Australia Prime Minister Tony Abbot said Sunday his nation is preparing to contribute 600 troops and up to 10 military aircraft to the campaign against the Islamic State group extremists.

For the last week, Kerry has traveled across the Mideast, to Turkey and finally Paris, to pin down nations on what kind of support they will give to a global coalition. But Kerry has refused to detail what countries have committed. He said some nations are still deciding whether their contributions will target foreign fighters or financiers helping the militant group, send more humanitarian aid to Syrian and Iraqi refugees, mount a propaganda campaign to decry the extremists’ brand of radical Islam or join a military mission.

Kerry cited reports that France is prepared to use air power against the Islamic militants. On Monday, Paris will host international talks seeking a strategy against the militants in Iraq, where they have overrun hundreds of miles of land in the country’s north and west.

But the militant group’s safe haven is in Syria among numerous Sunni rebel factions that have fought for more than three years to unseat President Bashar Assad.