Rebels in Ivory Coast have declared a state of emergency in areas of the country they are holding.
The rebels control the northern part of the country
They have accused President Laurent Gbagbo of preparing to go to war.
Disagreements over a power-sharing government have brought the two sides close to fighting again, four months after the civil war officially ended.
West African mediators have been trying to rescue the peace process after the rebels pulled out of the transitional administration in September.
In a statement, the rebels accused President Gbagbo of preparing to send his forces in to attack the two main rebel-held towns, Man and Bouake.
"We are on a state of maximum alert. That means that the soldiers are ready," rebel chief of staff Colonel Soumaila Bakayoko told Reuters news agency.
The Ivorian army denied it was planning to attack the two towns.
"It's completely untrue. We respect the ceasefire," said spokesman N'Goran Aka, adding however that the army would respond if the rebels broke the truce.
On Saturday, army chief of staff General Mathias Doue warned that the war could reignite.
"Resumption of the war is still possible, and at any time it could start again," he told a ceremony honouring the 186 members of the security forces killed since the rebellion started in September 2002.
One of the West African mediators in Ivory Coast, Ghanaian Foreign Minister Nana Akufo-Addo, told the BBC's Network Africa programme that the rebel declaration was "a further escalation" of an already difficult situation.
But he said that both rebel and army chiefs of staff were currently engaged in talks aimed at reducing tension.
The former rebel forces hold the north of the country, while government controls the south, separated by some 3,000 French peacekeepers.
West African leaders have been trying to negotiate a solution to the stand-off.
Any resumption of hostilities could easily spill over into neighbouring countries, with Ivory Coast home to millions of immigrants.