Who is Michael Flynn?

President-elect Donald Trump has selected retired Army lieutenant general Michael Flynn as national security adviser. Here's what you need to know about Flynn:

Flynn, 57, has been an outspoken critic of President Obama. He is highly regarded in the military and intelligence communities but was dismissed from the Pentagon’s top intelligence job in late 2014 for his combative style. He’s been a critical force shaping Trump’s world view that the United States is at war with “radical Islamic terrorism,” which stands in contrast to Obama, who’s warned against framing the war on terror along religious lines.

Flynn, who's never filled a policy role similar to national security adviser, was the top intelligence official in Iraq and Afghanistan during the height of the American involvement in the wars there. He is credited with helping to develop a system to exploit information captured on battlefields and using it to hunt down terrorists and destroy their networks.

“With each appointment made by the president-elect my grave concern about his presidency increases,” House Democratic Whip Steny Hoyer, D-Md., said in a statement.

Flynn is “a man who was fired by President Obama and who has made incendiary, hateful comments about Muslims,” he said. “This should alarm all Americans. In particular, I have serious questions about General Flynn’s competence and composure, his ongoing lobbying on behalf of the Turkish government and his links to Russia.”

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Last year, Flynn took a paid speaking engagement last year with Russia Today, a television network funded by the Kremlin, and sat next to Russian President Vladimir Putin at the network’s lavish anniversary party in Moscow.

Flynn’s loose ties to Russia and lobbying by his consulting group, the Flynn Intel Group, on behalf of Turkish interests, as reported by Politico, may have created difficulties if Trump had nominated him to an official Cabinet position. The national security adviser role does not require Senate confirmation.

The Flynn pick underscores that the hardline rhetoric about Muslims Trump espoused on the campaign trail will continue in the White House. Flynn has even stated that Islam is not a religion, rather a political ideology.