Trump names hostage negotiator Robert O'Brien as new National Security Adviser

US President Donald Trump on Wednesday named his point man for hostage situations, Robert O'Brien, to replace his hawkish national security advisor sacked last week.

"I have worked long & hard with Robert. He will do a great job!" Trump tweeted

Last week, Trump abruptly fired John Bolton, a vigorous proponent of using US military force abroad and one of the main hawks in the administration on Iran.

As the special presidential envoy for hostage affairs at the State Department, O'Brien worked closely with the families of American hostages and advised administration officials on hostage issues.

He previously helped lead the department's public-private partnership for justice reform in Afghanistan during the Bush and Obama administrations.

O'Brien comes into the new job with backing from Secretary of State Mike Pompeo and senior Republicans in Congress.

Bolton, by contrast, was a highly controversial figure in Washington. His instincts for an aggressive, interventionist foreign policy were at odds with Trump's more isolationist stance.

Trump said that one reason he fired Bolton was because he "wasn't getting along with people in the administration who I consider very important" and "wasn't in line with what we were doing".

O'Brien will become the fourth national security advisor in Trump's tumultuous first term.