Trump adviser O'Brien says possible poisoning of Navalny very concerning: Fox News interview

FILE PHOTO: National Security Advisor Robert O’Brien arrives before U.S. President Donald Trump delivers joint remarks with Israel's Prime Minister Benjamin Netanyahu on a proposed new Middle East peace plan in the East Room of the White House in Washington, U.S., January 28, 2020. REUTERS/Joshua Roberts

WASHINGTON (Reuters) - White House national security adviser Robert O’Brien said on Thursday the suspected poisoning of Kremlin critic Alexei Navalny was very concerning and it could impact U.S.-Russia relations.

“He’s a very courageous man. He is a very courageous politician to have stood up to (Russian President Vladimir) Putin inside Russia, and our thoughts and our prayers are with him and his family,” O’Brien said in an interview on Fox News.

“It’s extraordinarily concerning and if the Russians were behind this ... it’s something that we’re going to factor into how we deal with the Russians going forward,” he said.

Reporting by Eric Beech; Editing by Mohammad Zargham