Story highlights Donald Trump has taken to disparaging the organization on the campaign trail

Obama has pressed European nations to ramp up their military and financial support for NATO

Washington (CNN) President Barack Obama sought to highlight the United States' commitment to the 28-nation NATO alliance Monday, even as the leading Republican in the race to replace him has deemed the coalition "obsolete."

Obama met in the Oval Office alongside NATO Secretary General Jens Stoltenberg for more than an hour to discuss progress in the battle against ISIS and the response to last month's terror attack in Brussels, where NATO is headquartered.

While he didn't respond to questions shouted by the press about Donald Trump's derision of NATO, Obama did describe the alliance as intrinsic to American defense.

"NATO continues to be the lynchpin, the cornerstone, of our collective defense and U.S. security policy," Obama said. "It is because of the strength of NATO and the transatlantic partnership -- this transatlantic alliance -- that I'm confident that despite these choppy waters we will continue to be able to underscore and underwrite the peace and security and prosperity that has been the hallmark of the transatlantic relationship for so many decades."

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