America's top military leader has said US ground forces could be deployed again in Iraq, three years after they left the country.
Army General Martin Dempsey, the chairman of the Joint Chiefs of Staff, told a Senate panel that he would make the recommendation if the US strategy of airstrikes fails to defeat Islamic State (IS) militants.
"To be clear, if we reach the point where I believe our advisers should accompany Iraqi troops on attacks against specific ISIL targets, I will recommend that to the president," said Gen Dempsey, using another name for the terrorist group.
Asked to expand, he said he "would go back to the president and make a recommendation that may include the use of ground forces".
The four-star general said they could be sent to provide close combat advice or accompany Iraqi troops on any future mission to recapture the Iraqi city Mosul from the militants.
His remarks were soon contradicted by the White House's spokesman, who said commander-in-chief President Barack Obama "will not deploy ground troops in a combat role into Iraq or Syria".The president has already sent more than 1,000 US personnel, but they are said to be serving purely in an advisory role to help Iraqi troops tackle the IS forces.
On Tuesday, US warplanes stepped up their offensive against the IS in Iraq.
Two airstrikes were launched against sites northwest of Irbil and three southwest of Baghdad. American jets also pounded targets southwest of Baghdad in two raids on Sunday and Monday. French warplanes flying from the United Arab Emirates have meanwhile begun reconnaissance missions over Iraq.
Gen Dempsey also told senators the US was ready to strike the extremists in Syria.
"This will not look like 'shock and awe' because that is not how ISIL is organised," he said, "but it will be persistent and sustainable."
He appeared alongside Defence Secretary Chuck Hagel, who warned the war would not be easy or brief.