Story highlights Top officials have long been warning about the threat posed by ISIS

President Obama said the U.S. "underestimated" the group's rise in Syria

It was also hard to predict Iraq's defense capabilities, the White House says

ISIS, a top intelligence official said more than a year ago, has "ruthlessly grown in effectiveness."

In October a senior administration official said the terror group represented "a major and increasing threat" -- to the region and the United States.

Eight months ago, the military's top intelligence official warned ISIS "will attempt to take territory."

Those were the public assessments of ISIS coming from President Barack Obama's own administration dating back more than a year. So why is the President saying now his intelligence agencies misjudged the terror group, currently being pummeled by U.S. and coalition airstrikes?

In an interview with "60 Minutes," Obama admitted the U.S. "underestimated what had been taking place in Syria" that allowed the country to become "ground zero for jihadists around the world."

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He cited his director of national intelligence James Clapper, who told the Washington Post in mid-September the U.S. "underestimated ISIL [the government's name for ISIS] and overestimated the fighting capability of the Iraqi army."

Those remarks echoed Obama's own statement from early August, when he told reporters "intelligence estimates" hadn't accurately predicted ISIS' advances through Iraq and Syria.

In remarks and testimony, however, U.S. officials have been warning of ISIS' rise going back more than a year -- while at the same time warning of the limited intelligence-gathering capacity inside the countries where ISIS was expanding.

The warnings extend as far back as July 2013, when David Shedd, then acting as deputy director of the Defense Intelligence Agency, told a conference that al Qaeda-affiliated groups were gaining strength in Syria.

"It is very clear over the last two years they have grown in size, grown in capability and ruthlessly grown in effectiveness," he said at a CNN-sponsored panel at the Aspen Security Forum. "They will not go home when it is over. They will fight for that space. They are there for the long haul."

Since then, officials have warned that ISIS wasn't going anywhere -- including in October, when a senior administration official told reporters on a conference call that the danger from ISIS was intensifying.

"This is really a major and increasing threat to Iraq's stability ... and it's an increasing threat to us," said the official, who was previewing a visit to Washington by then-Iraqi Prime Minister Nouri al Maliki.

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The warning had ramped up by February, when the director of the Defense Intelligence Agency told lawmakers ISIS was looking to gain ground.

"[Al Qaeda in Iraq/ISIL] probably will attempt to take territory in Iraq and Syria to exhibit its strength in 2014, as demonstrated recently in Ramadi and Fallujah, and the group's ability to concurrently maintain multiple safe havens in Syria," Mike Flynn wrote in prepared testimony for the Senate Armed Services Committee.

The terror groups, Flynn wrote, had "exploited the permissive security environment to increase its operations and presence in many locations and also has expanded into Syria and Lebanon to inflame tensions throughout the region."

White House Press Secretary Josh Earnest said Monday that Obama wasn't blaming his intelligence services when he said they "underestimated" ISIS.

"The way that I would describe it is that everybody did; that everybody was surprised to see the rapid advance that ISIL was able to make from Syria across the Iraqi border and to be able to take over such large swaths of territory in Iraq did come as a surprise," Earnest said.

He added it was also difficult to assess ahead of time how well Iraqi security forces would be able to defend their own country because of the sectarian divisions in Iraq's government. He admitted there was some doubt that the forces would fend off ISIS's incursions.

"And I think that proved to be true in the end that ISIL was able to make significant gains because of the Iraqi security forces weren't able to withstand their advance," Earnest said.