Saudi Arabia has agreed to host training camps for moderate Syrian rebels as part of President Barack Obama’s broad strategy to combat Islamic State militants who have taken over parts of Syria and Iraq, U.S. officials said on Wednesday.

The agreement, outlined by Obama’s aides on the night of his speech to the American people laying out his expanded campaign against the Islamist group, appeared to reflect the depth of Saudi concern about Islamic State’s threat to the region.

Obama announced he had authorized stepped-up U.S. airstrikes in Iraq and for the first time would extend the aerial assault into Syria, where he also vowed to beef up support for moderate rebels fighting to overthrow Syrian President Bashar al-Assad. […]