<div>US President Donald Trump's administration was hit with a fresh resignation today as his top homeland security adviser, Tom Bossert – a presidential favourite – announced his departure from the White House.&nbsp;</div>''<div><br />''</div>''<div>White House Press Secretary Sarah Sanders said, the President is grateful for Tom's commitment to the safety and security of their country.&nbsp;</div>''<div><br />''</div>''<div>The announcement came a day after John Bolton took over as Trump's fourth National Security Advisor.</div>