Army Lt. Gen. Mike Flynn has accepted the position of national security adviser, the office of President-elect Donald Trump announced Friday.

Flynn, who advised Trump’s presidential campaign, had been considered a leading contender for the position, given his support of many of Trump’s most grave foreign policy proposals. Earlier this year, he defended Trump’s proposal to ban all Muslims from immigrating to the U.S. and said he was open to bringing back waterboarding as a torture method and to killing the families of accused terrorists, which constitutes a war crime under the Geneva Conventions.

Flynn served as the chief of the Defense Intelligence Agency but was forced out due to his controversial views on Islam and vocal opposition to the Obama administration’s policies to fight Islamic State. He claimed that “political correctness” was at fault in the U.S. efforts against terrorism. He also called Islam a “cancer” and argued that fearing Muslims is “rational.”

Fear of Muslims is RATIONAL: please forward this to others: the truth fears no questions... https://t.co/NLIfKFD9lU — General Flynn (@GenFlynn) February 27, 2016

Over the summer, he began receiving classified briefings as an adviser to Trump — while simultaneously working as a private consultant to foreign clients.

Flynn has also come under criticism for his ties to Russia, serving as an analyst for the country’s state-owned TV network RT and being paid to speak at the network’s anniversary gala.

Trump has said that he hopes to “reset” relations with Russia, and during his campaign even praised Russian President Vladimir Putin for being “a stronger leader” than President Barack Obama. Flynn, like Trump, believes that Russia and the U.S. should be closer collaborators in the fight against Islamic State, of which many foreign policy experts and Republican lawmakers are wary.

The position does not require Senate confirmation.

This article has been updated to reflect that Mike Flynn accepted the position.