American troops have stormed a Mexican beach setting off a diplomatic firestorm amid soaring tensions after Donald Trump threatened to bomb the country. US 'contractors' arrived by boat on Monday to 'Playa Bagdad', driving signs into the sand near where the Rio Grande empties into the Gulf of Mexico. Alarmed witnesses quickly alerted officials and heavily-armed Mexican security personnel rushed to the scene on trucks mounted with machine guns in a terrifying standoff.