UPDATE 1-Loud blast shakes Baghdad centre UPDATE 1-Loud blast shakes Baghdad centre (Updates with details) BAGHDAD, July 9 (Reuters) - A loud blast shook central Baghdad on Friday, sending a plume of white smoke into the air, and a U.S. security contractor said a mortar bomb had landed near a hotel housing Americans. "We had a mortar attack," the contractor told Reuters near the Al-Sadeer hotel as ambulances and police cars, sirens wailing, rushed to the scene. Witnesses said there were several injuries. A Reuters correspondent said the blast appeared to have occurred near the hotel, although this could not...