WASHINGTON • President Donald Trump's homeland security adviser, Mr Tom Bossert, will resign at the request of new National Security Adviser John Bolton, a person familiar with the matter said.

Mr Bossert has served in the White House since Mr Trump's inauguration. He has been a key adviser to the President on cyber security and headed up the White House's response to major hurricanes that struck Texas, Puerto Rico and the Virgin Islands last year.

But he resisted a reorganisation of the National Security Council last year that made him subordinate to the national security adviser, then General H.R. McMaster, the person said.

Mr Bossert, who was brought into the Trump administration by campaign adviser David Bossie, was regarded as an effective and professional figure by colleagues in the West Wing, especially after his handling of the storm response, a second person familiar with the matter said. He also had a good rapport with Mr Trump and knew how to communicate with the President.

His polished appearance and articulate TV style had made him a Trump favourite. But he lacked the star power of other top administration officials or the military credentials of the generals Mr Trump appointed as chief of staff and national security adviser, the person said. He was passed over to replace Gen McMaster, further diminishing his clout.

Mr Bossert is the second-high-ranking national security official to leave the White House since Mr Bolton began his job on Monday, following Mr Michael Anton, a spokesman for the National Security Council. Mr Anton's resignation was announced on Sunday; he will leave the post at a future date that has not been announced.

"The President is grateful for Tom's commitment to the safety and security of our great country," press secretary Sarah Huckabee Sanders said. "Tom led the White House's efforts to protect the homeland from terrorist threats, strengthen our cyber defences, and respond to an unprecedented series of natural disasters. President Trump thanks him for his patriotic service and wishes him well."

This year, the President has changed his secretary of state, national security adviser, and CIA director, among others.

BLOOMBERG, REUTERS, AGENCE FRANCE-PRESSE