Trump names O'Brien new national security advisor

President Donald Trump on Wednesday named his pointman 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.

O'Brien has until now served as Trump's envoy for situations involving US hostages abroad.