In a joint statement Saturday, 12 European embassies in the capital Kinshasa, and the Canadian embassy, called for calm.
"So long as the vote count is continuing, we call on all the parties involved... to show restraint," they wrote. The U.S. embassy issued a similar call the day before.
The call came as five opposition leaders said in a statement Saturday that they were organizing a protest march for next Wednesday. They included gynaecologist Denis Mukwege, the 2018 Nobel Peace Prize laureate, and former oil executive Martin Fayulu.
"We will protest against the irregularities noted during the voting operations," opposition leaders said in a letter to the governor of Kinshasa. Congolese police must greenlight the march.
Five other opposition candidates, including business magnate and former provincial governor Moise Katumbi, released a separate statement calling for the vote to be annulled, alleging it had been marred by "massive fraud."
At a press conference in the capital Kinshasa Friday, President of the independent electoral commission, CENI, Denis Kadima again rejected criticism by the opposition and independent observers that the extended vote had been chaotic and lacked credibility.
DRCONGO-VOTE
Around 44 million people in the nation of 100 million were registered to vote, with more than 100,000 candidates running for various positions.
President Felix Tshisekedi, 60, is running for re-election against 18 opposition candidates.
The sheer scale of the DRC — roughly the size of continental Western Europe — and its dire infrastructure make elections a stark logistical challenge.
The opposition and election observers said massive delays and bureaucratic chaos marred the vote on Wednesday, with election observers from the U.S.-based Carter Center noting "serious irregularities" at 21 out of 109 polling stations it visited. However, the African Union, which conducted an observation mission, said the poll had taken place in an atmosphere of calm but noted major logistical challenges.
Fraud allegations
Officially, the country's electoral commission, CENI, extended the vote only until Thursday for stations that had been unable to open on polling day.
One election officer meanwhile said late voting in a few places in the country's far east had been authorized for Sunday.
But ballots were still being cast on Saturday in remote areas, according to some officials, in a sign of continuing difficulties.
Macaire Kambau Sivikunula, an election official in the North Kivu region in the east of the country, told AFP that CENI had granted special permission for five voting stations to open on Sunday for voting.
He alleged that failure to get voting up and running on schedule had led to him and his family and other election officials receiving death threats. AFP did not confirm if local police had verified the accusation.
The poor but mineral-rich central African nation held four concurrent polls on Wednesday to elect the President, lawmakers for national and provincial assemblies, and local councilors.
On Friday evening, CENI released presidential results from the Congolese diaspora, which represents a minuscule proportion of the electorate, indicating a provisional lead for Tshisekedi.
The release of other results expected on Saturday was however postponed until Sunday.
Results from the DRC's 26 provinces are expected to start being released this week.
Some information in this report came from Reuters