Defense Secretary Ash Carter on Sunday blamed the Iraqi military's lack of "will to fight" for the ISIS takeover of the strategic town of Ramadi, while an Iranian general said it was the United States that was failing to confront the terrorist group, CNN and the Independent reported.

Asked why the Islamist militants -- who refer to themselves as the "Islamic State" and already control large swaths of territory across Iraq and Syria -- were able to take the city less than 70 miles west of Baghdad, Carter put the responsibility squarely on Iraq's Coalition-trained troops.

"What apparently happened was that the Iraqi forces just showed no will to fight," the secretary told CNN.

"They were not outnumbered," he said. "In fact, they vastly outnumbered the opposing force, and yet they failed to fight, they withdrew from the site, and that says to me, and I think to most of us, that we have an issue with the will of the Iraqis to fight ISIL and defend themselves," Carter added, using an alternative acronym for the terrorist group.

The Pentagon leader's comments unsurprisingly were not well-received in Baghdad, and Vice President Joe Biden on Monday spoke to the Iraqi prime minister, Haider al-Abadi, to reassure him of U.S. support, the Guardian noted.

Carter had been given "incorrect information," a spokesman for Abadi told The Associated Press.

"We should not judge the whole army based on one incident," the official urged.

The general in charge of Iran's paramilitary activities in the Middle East, meanwhile, insisted that the primary culprit in the ISIS advances was the United States itself.

"Today, in the fight against this dangerous phenomenon, nobody is present except Iran," Maj. Gen. Qassem Soleimani, commander of the elite Quds Force responsible for protecting Tehran's interests abroad, told the Tasnim news agency, the Independent noted.

The Mehr news agency, meanwhile, relayed the officer's direct challenge to the U.S. administration.

"Obama has not done a damn thing so far to confront (ISIS): Doesn't that show that there is no will in America to confront it?" Soleimani wondered. "How is it that America claims to be protecting the Iraqi government when a few kilometres away, in Ramadi, killings and war crimes are taking place, and they are doing nothing?"