Retired Lt. Gen Michael Flynn gestures as he arrives at Trump Tower, Thursday, Nov. 17, 2016, in New York. Retired Lt. Gen Michael Flynn gestures as he arrives at Trump Tower, Thursday, Nov. 17, 2016, in New York. FILE- In this file photo taken on Thursday, Dec. 10, 2015, Russian President Vladimir Putin, center right, with retired U.S. Lt. Gen. Michael T. Flynn, center left, and Serbian filmmaker Emir Kusturica, obscured second right, attend an exhibition marking the 10th anniversary of RT (Russia Today) 24-hour English-language TV news channel in Moscow, Russia. Flynn is widely reported Thursday Nov. 17, 2016, to be a potential contender to become national security advisor to U.S. president elect Donald Trump, although his appointment may be controversial. Retired Lt. Gen Michael Flynn walks through the lobby at Trump Tower, Thursday, Nov. 17, 2016, in New York.

Flynn has also been outspoken in his warnings about the dangers of Islamist groups, complaining on CNN in June that the U.S. needs to "discredit" radical Islam, but that "we're not allowed to do that right now." He accused the Obama administration in a New York Post op-ed in July of failing to design a coherent strategy for opposing the Islamic State group. And in August, he spoke at an event in Dallas for the anti-Islamist group Act for America, saying that Islam "is a political ideology" and that it "definitely hides behind being a religion."

Retired Lt. Gen Michael Flynn gestures as he arrives at Trump Tower, Thursday, Nov. 17, 2016, in New York. Retired Lt. Gen Michael Flynn gestures as he arrives at Trump Tower, Thursday, Nov. 17, 2016, in New York. FILE- In this file photo taken on Thursday, Dec. 10, 2015, Russian President Vladimir Putin, center right, with retired U.S. Lt. Gen. Michael T. Flynn, center left, and Serbian filmmaker Emir Kusturica, obscured second right, attend an exhibition marking the 10th anniversary of RT (Russia Today) 24-hour English-language TV news channel in Moscow, Russia. Flynn is widely reported Thursday Nov. 17, 2016, to be a potential contender to become national security advisor to U.S. president elect Donald Trump, although his appointment may be controversial. Retired Lt. Gen Michael Flynn walks through the lobby at Trump Tower, Thursday, Nov. 17, 2016, in New York.