"What we did is surrendered to a Jihadist organization and assumed there would be no consequences for that. We're seeing the consequences today," the former national security advisor said.
The former national security adviser's comments come after ISIS-K took credit for Thursday's deadly blast.
H.R. McMaster warned about potential threats to U.S. security that could arise after reducing military presence in Afghanistan early next year.
"It should be super-easy to condemn white supremacists," H.R. McMaster said.
"If the Russians can just use our own words against us, that's the best way to pull us apart from one another," Trump's former national security adviser said.
"Staying silent will only lead observers to infer that you care more about book royalties than, you know, who should be the president of the United States," Daniel W. Drezner wrote.
The art-of-the-deal president might finally have a national security advisor who'll enforce his preferences instead of undermining them.
H.R. McMaster Sr. died at a nursing home in Philadelphia last week.
The U.S. and its allies have "failed to impose sufficient costs" on Russia in response to repeated attacks, says Trump's top security official.
Kushner's approach was reportedly particularly concerning regarding his close relationship with Saudi Arabia's Crown Prince Mohammed bin Salman.
More than 20 people died in a week of protests in Iran, and Moscow's support for the regime's "nefarious designs" is a problem, the White House's top security adviser said.
The president says Iran is has "multiple violations of the agreement," but those around him don't seem to agree.
Trump's first year in the White House has been marred by persistent leaks at virtually every government level.
Steve Bannon's position in Donald Trump's White House is coming under increasing threat, according to reports.
Mike Cernovich claimed Trump's national security adviser drinks two bottles of red wine with his meals.