Who is John Brennan? CIA director who clashed with Donald Trump
The son of Irish immigrants is a fluent Arabic speaker and rose to the top of US intelligence in the wake of 9/11
CIA chief John Brennan has been blasted by Donald Trump over the leak of a controversial intelligence report.
Trump claimed the dossier, which included damaging allegations about the incoming president's sexual exploits, had been released by Brennan.
Businessman Trump was hitting back following Brennan's public advice that Trump should avoid "spontaneous" tweeting.
He warned: "Spontaneity is not something that protects national security interests."
Who is John Brennan?
The son of Irish immigrants to the US, Brennan's rise to the top of the Central Intelligence Agency marked the pinnacle of a career that saw him work with three presidents.
Nominated by President Barack Obama 2013, Brennan is most notable for his support of the US drone strategy.
Countries such as Pakistan, Libya, Somalia, Yemen and Afghanistan have be subject to strikes under Brennan's say-so.
He was voted to succeed outgoing David Petraeus by 12 votes to three in March 2013.
It marked a steady rise through the ranks of the intelligence service, where Brennan established himself as an expert in the Arabic-speaking world.
During his university studies, he would learn to speak Arabic fluently while studying at the American University in Cairo, Egypt.
Later, he read Middle Eastern Studies at the University of Texas.
How did John Brennan become CIA director?
After joining the agency following university, Brennan first worked as an analyst, eventually working his way to become the daily intelligence briefer for President Bill Clinton in the 90s.
By 1996 he was the CIA station chief in Saudi Arabia capital Riyadh.
Brennan quickly increased in seniority as the CIA's attention turn to Islamic fundamentalism following 9/11.
In 2004 he was appointed Director of the National Counterterrorism Center, and between 2009 and 2013 he was Homeland Security Advisor.
Barack Obama gave Brennan the nod of approval when he nominated him as the Agency's chief in 2013.
What is John Brennan's relationship with Donald Trump?
Brennan suffered a fraught relationship with incoming President Trump in the days before he stepped down as Agency chief.
He scolded Trump over his impromptu Twitter outbursts on issues of national interest and his relationship with Russia.
Brennan said: "Spontaneity is not something that protects national security interests and so therefore when he speaks or when he reacts, just make sure he understands that the implications and impact on the United States could be profound.
"It's more than just about Mr Trump. It's about the United States of America.
"I think Mr Trump has to understand that absolving Russia of various actions that it's taken in the past number of years is a road that he, I think, needs to be very, very careful about moving down."
Trump later hit back by hinting Brennan could have been behind a leaked dossier detailing Trump's sexual preferences.
He also attacked Brennan's record in the Syrian civil war and the Ukraine conflict.
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