Police fired tear gas and clashed with demonstrators in Lebanon’s capital on Saturday, at the start of a planned protest over this week’s massive explosion that devastated large parts of Beirut and killed more than 150 people. Thousands of people poured into Beirut’s main square, where they set up symbolic nooses to hang politicians whose corruption and negligence they blame for Tuesday’s explosion at the Port of Beirut. The huge blast was caused by thousands of tons of ammonium nitrate improperly stored at the port for more than six years, apparently set off by a fire.