Guinea's opposition called on Friday for the annulment of parliamentary elections held on September 28, alleging that the vote had been tarnished by widespread fraud.
The ruling party meanwhile said it was confident it would have a majority in parliament after the vote results are announced.
"The opposition demands the pure and simple annulment of the vote because fraud was so massive," the main opposition parties said in a joint statement read to journalists in Conakry.
"In spite of repeated warnings, the opposition notes that the authorities and the CENI (Independent National Electoral Commission) persist in publishing electoral results that in no way reflect the reality of the ballot," the statement added.
The various parties accused the regime of President Alpha Conde and his Rally of the Guinean People (RPG) party of carrying out an "electoral hold-up" in the troubled west African country, with the aim of "giving the presidential majority an undeserved victory".
A top presidential official said the ruling party was confident it would come out victorious.
"We know that we will have a majority in the next assembly," said Kridi Bangoura, presidential chief of staff. "We are not giving the results, but we know the trend."
The opposition coalition had already warned the RPG against "tampering" with votes as partial results trickled in after last Saturday's election, giving the lead to Conde's party.
On Friday, the opposition said that it "does not rule out resorting to any legal form of protest, including demonstrations across the whole of the territory," and the coalition urged its "supporters to remain mobilised and be ready" for rallies "in coming days."
The vote took place after many delays and was preceded by violent protests as the opposition accused Conde of conniving to rig it. Many shops in the capital Conakry shut down for days after the poll for fear of looting and further unrest.
Conde, who long led political opposition to late dictator Lansana Conte, became Guinea's first democratically elected president in 2010 in an election marred by delays and violent ethnic clashes.