Kinshasa - At least 42 people have been killed in three days of protests in Democratic Republic of Congo over a proposed legal reform the opposition says would keep President Joseph Kabila in power for years, a rights group said, three times the official estimate.Paul Nsapu, secretary general for Africa of the International Federation for Human Rights (FIDH), said that most of the victims had been killed by government security forces as they took part in political protests.The government, which says that only 15 people have been killed, said most of the victims were shot by private security guards while looting."For the most part these people were killed while they were advancing to protest," Nsapu told Reuters by telephone, adding that more than 100 people had been injured. "We don't expect the government to act in the same way as a rebel group."Live roundsIn a third day of protests on Wednesday, police fired teargas at demonstrators at the university campus in the riverside capital Kinshasa, a Reuters witness said. Clashes also took place in three other areas of the teeming riverside capital, security sources said.In the central neighbourhood of Matete on Wednesday, a witness reported security forces firing live rounds at protesters, who had erected barricades of burning tyres in the streets and responded by hurling rocks.The opposition called the protests on Monday to try to take control of parliament and stop pro-government legislators approving a reform of the electoral code that would require a census before the 2016 presidential vote. The opposition says that would take years to organise such a national count.Kabila came to power when his father was shot dead in 2001 and won disputed elections in 2006 and 2011. The constitution bars him from standing for a third term in next year's ballot.Little infrastructure and poor communicationKabila's allies say a census could be completed within a year, but opponents argue that it will take far longer in a nation the size of Western Europe, which has little infrastructure and poor communications.Government spokesperson Lambert Mende said at least 11 people were killed in Tuesday's violence, and four people on Monday.Mende said security guards had killed 10 civilians who were trying to loot private property on Tuesday, and a policeman also died."We registered no demonstration near the parliament building ... This was only pillage, extortion, destruction and vandalism," he added.