By Sushil Sharma
BBC News, Kathmandu
Maoist rebels in Nepal will not join the government unless "structural changes" of the state are put in place, their leader Prachanda has said.
The rebel chief says they are in no hurry to join the government
The rebels are known to favour an interim parliament to replace the present assembly in which they have no representation.
They also want a federal republic to replace Nepal's ceremonial monarchy.
The rebels called a truce after King Gyanendra ended direct rule and restored parliament in April.
The Maoists and a seven-party alliance of political parties clinched a landmark power-sharing deal in June.
Prachanda told the BBC that the rebels are in no hurry to join the government.
He did not elaborate on the kind of changes that the rebels wanted in the state structure.
The rebel chief's latest assertion has raised doubts over the early formation of the proposed interim coalition administration.
Such an uncertainty could affect the elections for the constituent assembly due to be held next year, although Prachanda pledged co-operation in holding them.
The government and rebels have differed recently over a government plan for the United Nations to be involved in the decommissioning of the rebels' weapons.
The two sides have also differed on the future of monarchy in the country.
The rebels have differed with the government over giving up arms
Prime Minister Girija Prasad Koirala has ruled out the dissolution of the present parliament and the induction of the rebels into the government without the arms management.
A UN team is due to arrive next month to monitor the arms management after the government and the rebels agreed to confine their troops within designated camps and barracks under UN supervision.
But difficulties remain, with mutually acceptable modalities of the arms management yet to be worked out.
The constituent assembly elections are key to ending the 10-year conflict that has left 13,000 people dead.
It will also decide the future of the monarchy which suffered a big blow in April after the pro-democracy movement, backed by the rebels, forced King Gyanendra to give up his absolute rule.
Most of the royal powers have been removed since then, but the rebels insist that the monarchy must be replaced by a republic.