BAGHDAD Black smoke is rising from a hotel in central Baghdad after a large explosion was heard in the area. Witnesses told Reuters that the hotel was destroyed and several people were killed. It's not yet known what caused the explosion. Gunfire was heard after the huge explosion. The hotel sits outside of the so-called Green Zone that encompasses the U.S.-led Coalition Provisional Authority (search). The U.S. military has told Fox News that from now until June 30, there could be an increase in violence in Iraq.