The United Nations Security Council voted on Monday to extend by a year its arms embargo against militia groups in eastern Democratic Republic of Congo.
The UN deployed 17,000 peacekeepers during the election
On Sunday, DR Congo held its first democratic poll in 40 years.
The election has been welcomed as a step towards peace. Final results will only be announced at the end of August. But concerns over instability in the east had led to fears that the election might fail. Voting there was overseen by a large UN peacekeeping force.
The Security Council resolution expressed concern that arms trafficking was fuelling and exacerbating conflicts throughout the region.
"The 15-member body noted that militias have been exploiting the DRC's natural resources to generate income to fund their activities," a UN statement said.
"The problem is most acute in the Ituri, North Kivu and South Kivu provinces in the east of the country, where the arms embargo began in 2003."
UN Secretary General Kofi Annan welcomed the DR Congo elections as "a milestone in the country's peace process," according to a statement from his spokesman.
South African President Thabo Mbeki - whose country hosted the peace talks that led to the election - also congratulated the Congolese people on the election.
"I take this opportunity to pay tribute to the Congolese religious community and all political parties for massively mobilising all sectors of society to participate in the making of history," Mr Mbeki said.
The elections were aimed at ending a long civil war, with 32 candidates, including incumbent Joseph Kabila, contesting the presidency.
Congolese describe their election hopes and fears
While many polling stations in the cities have already posted results, the large size of the country makes it unlikely that the finally tally will be available for several weeks.
It is still far from clear whether a second round will be required, or whether a candidate will gain the 50% of the votes needed to win outright, the BBC News website's Joseph Winter reports from Kinshasa.
Over 9,000 candidates stood for parliament. Some 25m voters were protected by 17,000 UN peacekeepers, most of them stationed in the east.
Mr Kabila, who came to power unelected in 2001, has told the BBC he will accept the result of Sunday's presidential elections, even if he loses.
Opposition leader Etienne Tshisekedi and his UDPS party boycotted the vote, and there were reports of violence on election day in Mr Tshisekedi's stronghold, the south-eastern Kasai region.
BBC world affairs correspondent Mark Doyle says the real test of the elections will be the acceptance of the results by all of the former warring parties.
The presidential candidates include the four vice-presidents who took office in 2003 in terms of a transitional power-sharing deal.
Three of the four vice-presidents are the leaders of former armed factions.
Some opposition candidates accuse Mr Kabila of being backed by the international community, and are already unofficially complaining about what they say are irregularities in the voting, our corresponent says.