US president Donald Trump named his fourth national security adviser in three years on Wednesday as he selected Robert C O'Brien to replace John Bolton.
Mr O'Brien is currently the state department's top hostage negotiator and recently travelled to Sweden to try to negotiate the release of rapper A$AP Rocky.
A lawyer by training, he is viewed as a mainstream Republican figure. He served under the George W Bush administration, and also advised former presidential candidates Mitt Romney and Ted Cruz. He has previously written about the threat from China and Russia to the US.
Mr Trump was effusive about his new pick. “I have worked long & hard with Robert. He will do a great job!” he tweeted.
It is understood that the US president was impressed by Mr O'Brien's work in securing the release of US hostages in Turkey and elsewhere. Mr O'Brien has also publicly praised the president, stating that he has had "unparalleled success in bringing Americans home without paying concessions".
