WASHINGTON – Two hours after the U.S. Consulate came under attack in Benghazi, Libya, the White House was told that a militant group was claiming responsibility for the violence that killed the U.S. ambassador and three other Americans.

A State Department email sent to intelligence officials and the White House situation room said the Islamist group Ansar al-Sharia claimed responsibility on Facebook and Twitter, and also called for an attack on the U.S. Embassy in Tripoli.

The document may fuel Republican efforts to show that the White House knew it was a terrorist attack, even as the U.S. ambassador to the United Nations was saying — five days afterward — that it appeared to be a protest gone awry.