Ten people have been killed in Nicaragua in three days of violent clashes between police and opponents of changes to the pension system, officials said on Saturday. The crisis occurred after the Sandinista National Liberation Front (FSLN) government decided to push through reforms that would apply a five per cent tax to old-age and disability pensions and increase the contributions paid by both employees and employers, the BBC reported. The violence began on Wednesday, when pensioners took to the streets in the capital and were joined the next day by thousands of students and workers. So far, at least 100 people have been injured. The dead include two protesters and a policeman who were killed in Managua on Friday, after demonstrations turned violent. The unrest continued into the night in several cities. Vice-President Rosario Murillo blamed the violence on "vampires demanding blood to feed their political agenda", but said the government was open to dialogue. It is the deadliest wave of unrest in Nicaragua since President Daniel Ortega returned to office for a second stint in 2007.The Sandinista government said public buildings were set on fire. Students from Polytechnic University in Managua barricaded their campus. Protesters accused riot police and government supporters of initiating the violence. Independent TV stations said they were taken off-air after broadcasting the demonstrations live.The measures were dismissed by businesses and experts as a tactic to stop the Nicaraguan Institute of Social Security (NISS) from going bankrupt. They also feared the reforms could increase unemployment, lower consumption and competition and harm the business climate.