Central Intelligence Agency Director John Brennan told a Senate panel on Thursday that the Obama administration's fight against the ISIS terror army hasn't set it on its heels, and the group is poised to infiltrate the U.S. and other nations.

'Unfortunately, despite all our progress against ISIL on the battlefield and in the financial realm, our efforts have not reduced the group's terrorism capability and global reach,' Brennan said during a rare open hearing of the Senate Intelligence Committee.

'In fact, as the pressure mounts on ISIL, we judge that it will intensify its global terror campaign to maintain its dominance of the global terrorism agenda.'

ISIL, not ISIS, is the Obama administration's preferred acronym for the jihadi army that controls large swaths of Iraq and Syria, and is developing a foothold in Libya.

NOT WORKING: CIA director John Brennan testified on Thursday that the Obama administration's efforts to fight the ISIS terror army 'have not reduced the group's terrorism capability and global reach'

SPIN CYCLE: President Barack Obama claimed Tuesday that his administration's anti-ISIS efforts were 'firing on all cylinders'

'ISIL has a large cadre of Western fighters who could potentially serve as operatives for attacks in the West,' Brennan said, cautioning that flows of refugees and ordinary travel paths could hide smuggled jihadis in plain sight.

The group is 'training and attempting to deploy operatives for further attacks' in western countries, he predicted.

President Barack Obama claimed on Tuesday that his military campaign against the self-proclaimed Islamic caliphate 'is firing on all cylinders.'

'ISIL is under more pressure than ever before,' he said, as the group 'continues to lose key leaders,' 'continues to lose ground in Iraq,' 'continues to lose ground in Syria' and 'continues to lose the money that is its lifeblood.

'We continue to destroy ISIL militarily,' Obama claimed.

But Brennan said the group has compensated for its losses of 1,000 to 3,000 militants in Iraq and Syria by recruiting and placing between 5,000 and 8,000 fighters in Libya.

'I am concerned about the growth of Libya as another area that could serve as the basis for ISIL to carry out attacks inside of Europe. ... That is very concerning,' he said.

TOUGH TERROR TALK: A senior policy adviser to Donald Trump (pictured) said 'Hillary Clinton's reckless foreign policy unleashed ISIS onto the world'

Donald Trump, the presumptive Republican presidential nominee, has been openly hostile to the Obama administration's terror-fighting approach.

And Stephen Miller, his senior policy adviser, told DailyMail.com that the Democratic presidential nominee is in large part to blame.

'Hillary Clinton's reckless foreign policy unleashed ISIS onto the world – from Libya to Egypt to Syria to Iraq – and her immigration policy gives them the means to attack us on our own soil,' he said.

'Director Brennan's testimony is a chilling warning that if we don't get immigration control in place we will allow both terrorists, and potential recruits, to burrow into the country.'

'Yet Hillary wants to increase Syrian refugees by 550 per cent,' Miller added, 'and bring in hundreds of thousands more from the most dangerous places on earth.'

Brennan predicted on Thursday that ISIS will become more aggressive and diversify its toolbox even as the U.S. ramps up efforts to stop it.

'To compensate for territorial losses, ISIL will probably rely more on guerrilla tactics, including high-profile attacks outside territory it holds,' he warned.

PROBLEM: Brennan said ISIS will ramp up its terror operations in the western world, and has compensated for troop losses in Iraq and Syria with an expanded footprint in Libya

Brennan told senators that the CIA has 'not been able to uncover any direct link' between foreign terror groups and the Islamist who killed 49 people at a gay nightclub last weekend in Orlando, Florida.

The man pledged his allegiance to ISIS during a 911 call he placed in between bursts of gunfire.

The CIA director underscored the ability of ISIS to rally so-called 'lone wolf' acolytes around the world, calling the Orlando murders a 'heinous act of wanton violence' and an 'assault on the values of openness and tolerance' that define the United States as a nation.

Majorty Leader Mitch McConnell said Thursday on the Senate floor that ISIS 'is not "contained",' and called it 'the personification of evil in our world, and it will continue to bring tragedy after tragedy to our doorsteps until it is defeated.'