U.S. Senate Intelligence chairman says threat on social media remains

Senator Richard Burr, the Republican chairman of the U.S. Senate Intelligence Committee, said on Wednesday that the "national security vulnerability" and "unacceptable risk" of social media platforms remain unaddressed.

Burr spoke at a committee hearing where top executives from Facebook Inc and Twitter Inc were testifying on Wednesday about foreign entities' use of social media to influence U.S. political discourse.

(Reporting by Patricia Zengerle Editing by Susan Thomas)