The success piles pressure on Damascus and Baghdad and throws doubt on a U.S. strategy of relying almost exclusively on air strikes to support the fight against ISIS.
Islamic State now controls more than half of Syrian territory following four years of civil war.
The advance of Islamic State has exposed the failings of Iraq's army and the limitations of U.S. airstrikes.
ISIS fighters who overran Ramadi in a major defeat for the Iraqi government and its Western backers are flying back flags on key buildings and setting free prisoners.
The United States is discussing imposing further sanctions against the reclusive country, as it is "not even close" to taking steps to rein in its nuclear weapons program.
The U.S.-led coalition stepped up air raids against Islamic State, conducting 19 strikes in the vicinity of Ramadi over the past 72 hours.
The wreckage of a U.S. military helicopter lost on an earthquake relief mission was found high on a mountainside in Nepal.
Hosting the six-nation Gulf Cooperation Council for a rare summit at Camp David, Obama pledged to help counter Iran's "destabilizing activities in the region."
Tension over U.S. policy toward Tehran, Syria and the Arab Spring uprisings will loom over the meetings.
The new generation of Arab leaders appear more assertive than their fathers, want a range of alliances instead of dependence on Washington, and may be readier to say 'no' to their main ally.
U.S.-Russian relations are at their lowest ebb since the Cold War.
The U.S. is aiming to finalize a deal by June 30 that puts limits on Iranian programs that could be used to make nuclear arms.
Analysts and diplomats in the Middle East described King Salman's decision to skip a meeting at Camp David this week as a snub, despite denials from U.S. officials and Saudi insiders.
Today marks the 70th anniversary of the victory by Allied forces over Nazi Germany in 1945.
The U.S. military has started training Syrian fighters to combat Islamic State militants, officials said, adding the program had begun in Jordan and would soon launch in Turkey.
The President is expected to make a renewed push to help Gulf allies create a region-wide defense system to guard against Iranian missiles.
Washington wants to be certain that any nuclear deal between Iran and major powers includes the possibility of restoring U.N. sanctions if Tehran breaks the agreement.
Federal agents for years monitored one of the two gunmen who were shot dead after opening fire with assault rifles at a heavily guarded Texas exhibit of caricatures of the Prophet Mohammad.
Britain's newborn princess has been named Charlotte Elizabeth Diana.
Britain's Duchess of Cambridge, the wife of Prince William, gave birth to a girl on Saturday.