The UN Security Council has condemned "the heinous and cowardly murder" of U.S. journalist James Foley by Islamic State militants.
In a statement adopted on August 22, the 15-nation council said the militants and their ideology of intolerance must be defeated.
The militants released a video this week showing one of the group's fighters beheading Foley and threatening to kill a second American reporter, Steve Sotloff.
Earlier, the White House said the United States stands ready to take additional action against Islamic State fighters and will not be restricted by the Iraq-Syria border.
White House deputy national security adviser Ben Rhodes told reporters the murder of Foley was a "terrorist attack" against the United States.
Rhodes said the group is more dangerous today than it was six months ago.
U.S. officials this week disclosed an attempt that failed to rescue U.S. hostages held by Islamic State militants.