Following President Barack Obama's admission that the US "underestimated" the threat posed by the Islamic State, reports are circulating that ISIS militants could be as close as one mile from Baghdad.

According to the BBC's Lyse Doucet in Baghdad, members of the terrorist group were less than 10km from the city in the early hours of this morning.

The Foundation for Relief and Reconciliation in the Middle East then reported at around 6am GMT that IS militants were "less than 2km away from entering Baghdad".

"They said it could never happen and now it almost has. Obama says he overestimated what the Iraqi Army could do. Well you only need to be hear a very short while to know they can do very very little [sic]," an update from the Foundation states.

This information comes in the wake of a candid interview with Obama which aired on CBS on Sunday, in which the President said it is "absolutely true" that the administration underestimated the power of the Islamic State, as well as the ability of the Iraqi army to counter the threat posed by extremists.

Obama insisted that must be a "generational challenge" to the way that tolerance is understood in places like Iraq and Syria, where Islamist groups are gaining momentum.

"We cannot do this for them because it's not just a military problem. It is a political problem. And if we make the mistake of simply sending US troops back in, we can maintain peace for a while," he said.

"But unless there is a change in how, not just Iraq, but countries like Syria and some of the other countries in the region, think about what political accommodation means. Think about what tolerance means... I think there's going to be a generational challenge. I don't think that this is something that's going to happen overnight."

The BBC reports that there has been "fierce fighting" between ISIS and government troops to the west of Baghdad, and intense airstrikes from the US-led coalition against the jihadists.

However, "the insurgents have not retreated".

"The Islamic State are on the verge of entering Baghdad...Over 1,000 Iraqi troops were killed by them yesterday," warned Canon Andrew White, vicar of Baghdad this morning.

"As I said all military strikes are doing nothing. If we ever needed your prayer it is now."