This file photo shows fighters of the Islamic State of Iraq and the Levant (ISIL) standing guard at a checkpoint in the northern Iraq city of Mosul, June 11, 2014. Reuters

ISIS, the radical Islamic group that has routed the Iraqi army, is not yet capable of carrying out its threat to attack the U.S. and President Obama wants to "make sure that they never can," Secretary of State John Kerry told ABC News today.

The leader of ISIS, Abu Bakr al-Baghdadi, has made threats to attack Americans and other western countries, and Britain's Prime Minister David Cameron recently said he fears ISIS is a danger to the West.

"They have indicated a desire to do so. They've already indicated and the rhetoric has embraced attacks against the West," Kerry said.

But when asked whether ISIS has the ability to strike the U.S., Kerry said, "Not yet."

"Certainly one of the considerations we have is to make sure that they never can. But that's exactly what the president is busy trying to determine now, is: What is the best way to approach that so that we are most effective and, frankly, in a way that is sustainable over the long haul?" he said.

Kerry said Monday that Obama is already lining up ISIS targets and has reserved the right to launch attacks on the group if he feels it is necessary.

Obama Lining Up ISIS Targets and Keeps 'Prerogative' To Strike

Iraqi Military Out of Hellfires in Battle Against ISIS

Obama To Send Up To 300 U.S. Military Advisers To Iraq

ISIS, an al-Qaeda offshoot which stands for the Islamic State of Iraq and Syria, surprised the U.S. with its lightning advance that has left much of northern and western Iraq in its hands as well as much of northern Syria. Its fighters are now poised to attack the Iraqi capital Baghdad.

The collapse of the American trained army and the instability of the Iraqi government after the U.S. spent eight years rebuilding the country has left the U.S. open to questions that it abandoned Iraq.

But Kerry that more that more face-to-face engagement with Iraq's leaders would not have avoided the crisis with Sunni extremists.

"Things have happened here that have been negative, absolutely. But most people here will tell you it's not because of the absence of the United States. It's because the Iraqi government has not been responding adequately to the needs that have been expressed," Kerry told ABC News.

Before trips to Baghdad and Irbil over the past two days, Kerry had only visited Iraq once as Secretary of State, early last year. His predecessor Hillary Clinton had also only visited once. But Kerry noted that Vice President Biden had been "managing that file" for a period of time before the latest violence broke out, and Deputy Assistant Secretary of State for Iran and Iraq Brett McGurk has been in the area frequently as well.

He said he was hopeful that the Iraqi political class would install a new, inclusive leadership after parliament convenes on July 1 and said that his visit to Baghdad demonstrated that was a real possibility.

"The Sunni leaders that I met with, the current leaders I met with this morning, and even some of the Shia leaders I met with yesterday are all determined to follow the constitutional process to try to form a government that can be a unity government and that can pull people together," he said.

Kerry declined, as he has repeatedly in recent days, to say whether the United States has faith in Prime Minister Nuri al-Maliki, saying the decision of who should lead the Iraqi people is one best left to the Iraqis.