US to use Facebook, Twitter to issue terror alerts

According to a draft Homeland Security Department plan obtained by The Associated Press, the public could see the warnings on Facebook and Twitter.

The colour-coded system has been one of the government's most visible counter-terrorism tools since the September 11, 2001 attacks.

The government's terror warnings could be withheld from the public entirely if announcing a threat would risk exposing an intelligence operation or a current investigation, according to the government's confidential plan. The new system is expected to be in place by April 27.