Second night of Northern Irish riots ahead of Clinton visit By Ian Graham BELFAST (Reuters) - A number of police officers were injured in Northern Ireland on Wednesday in a second night of rioting this week, just two days before U.S. Secretary of State Hillary Clinton visits to lend support to the province's fragile peace. Up to 1,600 pro-British loyalists, enraged at a decision by nationalist councilors to remove the Union Jack flag from above the entrance of Belfast City Council, battled again with police, 15 of whom were injured after the council decision on Monday. Police fired plastic bullets when they came under attack with bricks, bottles and other missiles in Carrickfergus, county Antrim, a few miles outside Belfast. Four people were arrested, a police spokesman said and police officers were injured, though he declined to give a number. An office belonging to the centrist, non-sectarian Alliance Party, whose support enabled nationalists vote to bring down the British flag, was also ransacked and set on fire during the rioting, according to a spokesman for the fire services. One of the party's members of parliament for Belfast, Naomi Long, said earlier on Wednesday that she had received death threats over the council's decision. The violence was condemned by pro-British unionists, whose loss of their Belfast City Council majority last year prompted the vote to remove the flag on all but 17 days of the year after it had flown continuously for more than 100 years. "People are entitled to peacefully protest but there is absolutely no justification for the carnage which has been caused in Carrickfergus this evening," said Sammy Wilson of the Democratic Unionist Party (DUP), which shares power with pro-Irish Sinn Fein. Clinton, whose husband helped broker a 1998 peace deal that largely ended 30 years of sectarian violence in which more than 3,600 people died, will meet political leaders on Friday when she ends a five-day European tour in Belfast. Reporting by Ian Graham; Editing by Padraic Halpin and Jon Hemming