The clashes, including mortar and rocket fire, shook Kinshasa for some three hours around the residence of Vice President Jean-Pierre Bemba, the challenger to the incumbent president and favourite to win the election, Joseph Kabila.
The United Nations sent in extra armoured vehicles to boost its presence in the area and European Union helicopters overflew the scene after the firing was heard.
Kinshasa Governor Baudouin Liwanga said late on Saturday that a soldier and three civilians, a woman and two men, had been killed during the clashes. He did not provide details on how they had died.
He announced on state television that all public gatherings and demonstrations were banned in the capital and extra police patrols had been ordered to restore order.
Members of Vice President Bemba's military guard told AFP they were involved in a firefight with elements of the Republican Guard, loyal to Kabila.
Interior Minister Denis Kalume Numbi went on television to warn that the army would move in if calm was not maintained, after two hours of firing in the morning.
He said the clashes had been sparked by young street gangs who blocked off a street near Bemba's residence, backed up by armed fighters supporting the vice president.
In the morning, mortars and rockets were fired from a cemetery in the La Gombe district occupied by the Republican Guard, a few hundred metres (yards) from Bemba's residence.
Bemba was not at his official residence when the firing took place, his spokesman Moise Musangana told AFP. An AFP photographer reported seeing a wounded member of Bemba's guard coming from the direction of the cemetery.
The director of Bemba's office Fidele Babala told AFP by telephone that members of Kabila's Republican Guard in the cemetery had fired rockets but that the firing appeared to have died down by late morning.
"We are doing everything to calm the situation," Babala said.
The noise of firing from the direction of the cemetery appeared to cease from around 1200 GMT.
Meanwhile, the head of the UN mission in the country (MONUC) William Swing, met Bemba at his private residence. Accompanied by the Senegalese commander of MONUC forces, Babacar Gaye, Swing was to demand that Bemba urge calm among his supporters, a diplomat said.
A Western military officer requesting anonymity said he had no indication that the Republican Guard had deployed against Bemba's men, but confirmed clashes between youths and police in the area of his residence.
He told AFP that light arms fire had been exchanged between police and young street gangs backed up by civilian fighters armed by Bemba's guards. "It is difficult to say who fired and we have no toll" of casualties, he said.
The fighting came as the country's Electoral Commission published updated partial results of the second round of the presidential election, held on October 29.
With 80 percent of ballots counted Kabila was down more than one percent from on Friday on 59.6 of the vote, but held his lead over Bemba who gained just over one point to 40.4 percent.
The figures were based on fresh partial results published on the website of the Independent Electoral Commission and added together by AFP. Turnout was 65 percent in the 136 constituencies so far counted.
Provisional full results are due to be published on November 19.
Thousands of UN and European Union troops are stationed in the country to keep the peace during the election period. When results were released in August from the first round of voting, troops loyal to the rival candidates clashed in the capital, causing at least 23 deaths in three days.
The elections were the first multiparty polls in more than 40 years in this vast central African nation, and a key stage in its recovery from five devastating years of civil war.

Copyright AFP (Agence France-Presse), 2006