Former national security adviser H.R. McMaster has accused some unnamed White House advisers of being “a danger to the Constitution” by trying to manipulate President Trump to achieve their own ulterior motives.

McMaster, who was rumored to be at loggerheads with Trump for months before his departure in March 2018, stopped short of offering his own assessment of the president while making the remarks Wednesday at an event hosted by the Foundation for Defense of Democracies. But he suggested that at least two distinct groups of advisers to the president are secretly running point on agendas that are at odds with those of Trump himself.

One group, he said, consists of those “who are not there to give the president options—they’re there to try to manipulate the situation based on their own agenda, not the president’s agenda.”

The other group “cast themselves in the role of saving the country, even the world, from the president,” he said.

“I think those latter two categories of people are actually a danger to the Constitution of the United States,” he said.

While McMaster did not identify any White House advisers in his warning, it appeared to echo a claim about an internal “resistance” made in an explosive anonymous op-ed published by The New York Times last year. The op-ed, whose author claimed to be a senior official in the Trump administration, said several officials worried about Trump’s “erratic” behavior were intentionally thwarting parts of his agenda to stop his “worst inclinations.”

McMaster, a retired Army lieutenant general, joined the administration's inner circle after Trump’s first national security adviser, Michael Flynn, was abruptly fired after a few weeks on the job.