Small groups of protesters also torched tyres in several parts of the city.

It was the first violence since mass protests in April forced the king to end palace rule and recall parliament.

MPs were due to discuss a proclamation drastically reducing the king's powers on Monday, but political parties put off the debate until later in the week.

Pro-democracy movement

"Beware, don't betray the people," the Associated Press quotes the protesters as chanting as they marched towards the city centre.

"I don't think these leaders are capable of doing this," said Govinda Rayamajhi, one of the protesters, referring to the special proclamation that needs to be approved by parliament.

"This protest is to put pressure on them. We have to continue to fight to win our rights," he told Reuters.

Home Minister Krishna Sitaula told reporters that the government was determined to table the proclamation in parliament shortly.

The proposals are aimed at ending the king's control over the army, putting the 90,000 troops under the direct control of parliament and bringing the royal family and its assets under the tax net.

Cutting the king's powers is a key demand of pro-democracy protesters and Maoist rebels, who began fighting for a republic 10 years ago.

The BBC's Sushil Sharma in Kathmandu says that there have been reports of differences among top leaders over the issue of curtailing royal powers, which they want to sort out before making the final decision.

But our correspondent says that once the move is presented in the parliament, it is certain to be adopted, as the parties represented in the government account for more than 90% of the 205-member chamber.

Attitudes hardened significantly towards King Gyanendra and the monarchy itself after he seized direct control in February 2005.