The rebel ceasefire, first announced for three months in September and later extended for another month under popular pressure, is due to expire at midnight on Monday.

King Gyanendra, who seized absolute power 11 months ago, has refused to match the truce while the guerrillas have accused his royalist government of provoking them to break it.

Still, the four months saw fewer killings.

"An end to the ceasefire would naturally mean resumption of violence," said Yubaraj Ghimire, editor of Samay, a weekly magazine. "But there is still some hope that the Maoists will continue with their unilateral ceasefire for some time."

The truce neared its end amid unconfirmed reports that the Maoists, who hold sway in the countryside, were now setting their sights on the high-security capital, Kathmandu, which has so far been spared major attacks.

The rebels are fighting to establish one-party communist rule in the mountainous Himalayan nation, one of the world's poorest.

The revolt, now nearly 10 years old, has killed more than 12,500 people and delayed national as well as local polls.

On Friday, United Nations Secretary-General Kofi Annan expressed concern that fighting could resume and urged the government to join the ceasefire.

Annan also called on the rebels to extend the truce, saying that the people had benefited from the de-escalation of violence in the last four months.

But analysts said the royalist government, which asserted recently that it had broken the rebels' "backbone", was unlikely to take heed as it believes the rebels cannot be trusted.

"Continued refusal by the state to reciprocate the ceasefire would not only discredit it further but establish that it is the government which is more responsible for the possible resumption of conflict and the likely bloodshed," Ghimire said.