Congolese opposition parties rejected on Saturday partial results released by the electoral commission giving incumbent President Joseph Kabila an early lead in the vote count from the November 28 presidential election.

In a joint statement signed by major parties, including that of veteran opposition leader Etienne Tshisekedi, the opposition cited irregularities and said the electoral commission was psychologically preparing the population for fraud.

As a consequence, we reject these partial results and consider them null and void, the statement read out by Vital Kamerhe said.

It added that the manner the commission was releasing the results was illegal.

The opposition called for mediation by other African leaders, but rejected forming a government of national unity with Kabila.

Partial results released by the electoral commission (CENI) showed Kabila leading with 3,275,125 votes, while Tshisekedi trailed with 2,233,447 votes, based on 33.3 percent of polling stations counted.

The tally included virtually no results from the capital Kinshasa, where Tshisekedi is confident of strong support. The percentage of votes counted varied widely by province.

UDPS Secretary General Jacquemain Shabani Lukoo told Reuters that the government risked sparking violence over the alleged massive fraud.

If they carry on like this there will be trouble, that's for sure, we will not let this lie, he told Reuters.

The commission said it was forced to released the partial results after hackers managed to publish fake numbers on its official website that appeared to give Tshisekedi a strong lead.

(Reporting by David Lewis and Jonny Hogg; Writing by Bate Felix; Editing by Michael Roddy)