Western countries and the U.N. urged calm in the Democratic Republic of Congo after President Joseph Kabila was declared the winner in disputed elections. Gunfire range out in the capital city of Kinshasa, an opposition stronghold where bout 20,000 army soldiers were on standby, riot police patrolled and smoke from burning tires could be seen, the BBC reported. Meanwhile, police in London say they arrested 143 people protesting the election. Etienne Tshisekedi, the main opposition candidate, has rejected the official results and declared himself the winner, heightening fears of violence. Kabila had captured 49 percent of the vote to 32 percent for Tshisekedi, Daniel Ngoy Mulunda, election commission chief, announced Friday evening. Kabila backers, mainly in the eastern part of the country, cheered and held victory parades. But Tshisekedi, 78, said his party\'s calculations give him 54 percent of the vote to 26 percent for Kabila. \"I reject these results, and in fact I see them as a provocation against our people,\" Tshisekedi said. \"It is scandalous and vulgar. His term is finished. I am the president.\" Tshisekedi later urged his supporters to \"stay calm and peaceful.\" United Nations Secretary-General Ban Ki-moon, the European Union, the United States, France and Belgium urged calm. Ban called for \"any differences regarding the provisional results of the polls to be resolved peacefully through available legal and mediation mechanisms.\" The French Foreign Ministry called on \"all Congolese political players to show restraint and a spirit of responsibility.\" U.S. State Department spokeswoman Victoria Nuland, in a statement, urged the country\'s leaders and their supporters to \"act responsibly, to renounce violence, and to resolve any disagreements through peaceful dialogue and existing legal remedies.\"