White House: Islamic State's 'barbarity knows no bounds'

WASHINGTON — The United States is condemning the purported killing of 21 Egyptians by militants in Libya affiliated with the Islamic State group as "despicable" and "cowardly."

White House press secretary Josh Earnest adds in a statement Sunday that the group's barbarity "knows no bounds."

Earnest says the killings underscore the need for a political resolution to the conflict in Libya. He says the situation in Libya only benefits terrorist groups, and he called on the Libyan people to unite in opposition to terrorism.

Also Sunday, Secretary of State John Kerry called Egyptian Foreign Minister Sameh Shoukry. He offered his condolences on behalf of the American people and strongly condemned the killings. Kerry and the foreign minister agreed to keep in close touch as Egyptians deliberated on a response, according to a release from the State Department.

Video purporting to show the mass beheading of Coptic Christian hostages was released Sunday by IS.

The Associated Press could not independently verify the video. But the Egyptian government and the Coptic Church, which is based in Egypt, have said the video is authentic.