Sebastian Gorka has become the latest member of Donald Trump's team to leave the White House.
The right-wing British deputy assistant to the president cited "forces" that do not support the "Make America Great Again" agenda as the reason for departure.
A White House official said: "Sebastian Gorka did not resign, but I can confirm he no longer works at the White House."
The circumstances surrounding Mr Gorka's departure were unclear.
"Regrettably, outside of yourself, the individuals who most embodied and represented the policies that will 'Make America Great Again,' have been internally countered, systematically removed, or undermined in recent months," the national security adviser wrote, according to Politico.
