WASHINGTON (AP) — President Barack Obama on Friday played down the prospect of speedy U.S. intervention in Syria, stressing the difficulty of ordering military action against the Assad government without a strong international coalition and a legal mandate from the United Nations.

Defense Secretary Chuck Hagel said Obama has asked the Pentagon to provide military options in light of reports that the Syrian government used chemical weapons against civilians. While Hagel declined to discuss any specific force movements, U.S. defense officials said the Navy moved a fourth warship into the region. Each can launch ballistic missiles.