The head of the Democratic Republic of Congo's election commission has warned against publishing unofficial results from Sunday's presidential election.
UN peacekeepers are providing crucial logistical support to the vote
Apollinaire Malumalu said that the publication of partial results could provoke violence.
A previous round of voting saw clashes between the armed supporters of the two front-runners when results came out.
President George W Bush has ordered the assets frozen of people he says are contributing to conflict in DR Congo.
Supporters of the two candidates, President Joseph Kabila and Jean-Pierre Bemba, have been sending e-mails and text messages purporting to give interim results from the vote count, Reuters news agency reports.
Mr Malumalu, said he was concerned about "false and premature statements on the results" which could increase tension.
International observers have generally praised the vote as being well-run, despite some disruptions in the north-east of the country.
But the BBC's Mark Doyle says the atmosphere in the capital Kinshasa is even more tense than usual.
He says everyone remembers the clashes that broke out in August after results of an earlier round of voting in the election were published.
ASSETS FROZEN BY US:
Laurent Nkunda: founder, National Congress for the People's Defence
Ignace Murwanashyaka: president, Forces Democratiques pour la Liberation du Rwanda
Khawa Panga Mandro: former president, Party for Unity and Safeguarding of the Integrity of Congo
Viktor Anatolijevitch Bout: owner, Great Lakes Business Company
Sanjivan Singh Ruprah: businessman
Dimitri Igorevich Popov: general manager, Great Lakes Business Company
Douglas Mpano: manager, Great Lakes Business Company
Supporters of Mr Kabila and his rival Mr Bemba fought with tanks and heavy weapons in the streets of Kinshasa.
Mr Malumalu has not said if results will be announced before the deadline of 19 November.
Counting the votes is a time-consuming process as all the ballot papers must be transported from sometimes remote locations to compilation centres.
DR Congo is two-thirds the size of western Europe and has just 300 miles of paved roads.
The country's rich reserves of minerals such as gold, diamonds and coltan - used in mobile phones - have attracted a series of armed groups, both Congolese and foreign, intent on looting.
President Bush ordered a freeze on the assets of seven political figures and businesspeople that he says have contributed to the conflict in DR Congo.
The executive order also bars Americans from doing business with them and calls for the same measures to be taken against those who recruited children to fight in the country.
In a letter to Congressional leaders, Mr Bush said the Congolese conflict had been marked by serious human rights violations by militias, including the massacre of civilians, sexual violence and the use of child soldiers.