Six people have been killed in an attack on a residence of the president of the Democratic Republic of Congo. An "unidentified group of armed men" attacked the residence of President Joseph Kabila in the capital, Kinshasa, a government spokesman said, describing the raid as an attempted coup. Mr Kabila's guards killed six of the men, the spokesman said. Joseph Kabila took power in 2001 after his father, President Laurent Kabila, was assassinated. He was later elected in his own right. Plagued by violence In 1998, DR Congo was plunged into a war in which more than five million people died - the deadliest conflict since World War II. The conflict formally came to an end through a peace deal in 2003, but the east of the country is still plagued by army and militia violence. "We have witnessed a coup attempt," said Information Minister Lambert Mende, according to Reuters news agency. "A group of heavily armed people attacked the presidential palace. They were stopped at the first roadblock." President Kabila was not in the building at the time of the attack at 1330 local time (1230GMT), Mr Mende said. In addition to the six men killed, several others were detained, he added. On 15 January, parliament backed a proposal by Mr Kabila to reduce presidential elections from two rounds to one. The change means the winner can claim victory with less than 50% of the vote. Presidential and parliamentary elections are scheduled to take place in November 2011.