Nepali police fired rubber bullets at thousands of protesters Sunday, struggling to enforce a curfew imposed to keep persistent pro-democracy demonstrators off the streets in the Himalayan country's deepening crisis.

The protesters were trying to enter the city limits of Katmandu, the capital, when police first fired tear gas, then rubber bullets, independent Kantipur television reported. Doctors at a hospital said they treated three people injured by rubber bullets.

Katmandu was under a daylong curfew for the fourth straight day. On Saturday, clashes between security forces and tens of thousands of demonstrators left more than 200 people injured.

The protesters have refused to quit despite King Gyanendra's offer to allow the alliance of seven opposition parties behind the protests and a general strike to nominate a prime minister and form a government.

Opposition leaders said the king's offer to resolve a crisis that began after he seized power in February 2005 fell short of a key opposition demand: the return of parliament and creation of a special assembly to write a constitution.

The chaos has stoked worries among the international community of a humanitarian crisis in Nepal, already one of the world's poorest countries.

Many also worry that a political vacuum could give the Maoist rebels — who have seized control of much of the countryside in a bloody, 10-year insurgency — a route to power.

The opposition called for protests to continue throughout the week, including a massive rally along the ring road that skirts the capital on Tuesday.

"We urge all the people, the old and the young alike, to come out of their homes, their villages, their neighborhoods and get to the nearest point on the ring road for the mass rally," said a statement from body coordinating the protests.

Sunday's curfew was to last 11 hours in and around the capital, but state television later reported that it had been shortened by an hour and would end at 7 p.m.

The army strung barbed wire to block off some inner alleys and major intersections in Katmandu on Sunday. Small groups of protests protested inside the city as soldiers patrolled in armored personnel carriers.

Thousands of other people marched elsewhere in Katmandu's Kalanki and Gangabu neighborhoods — which have been the center of the protests since the opposition campaign to force out King Gyanendra began April 6.

By late afternoon, the protests had degenerated into young men hurling bricks and bottles at police, who responded with tear gas and baton charges.

Smaller protests also broke out on the ring road. While most followed what has now become a common routine of chanting and waving flags, an ominous development was attacks on people accused of being government informers.

At one rally, a man was severely beaten after being accused by a political party organizer, Gita Pathak, of being an informer.

"He works for the palace," she screamed as a gang of men beat the victim to the ground, showering him with kicks before he was spirited away by some onlookers.

In the southern town of Bharatpur, hundreds of women chanted slogans against the king, banging plates and utensils.

In Nepalgunj, 310 miles southwest of Katmandu, farmers came out with plows to protest. Some broke down the statue of King Tribhuwan, Gyanendra's grandfather.

Nepal's crisis has escalated since a general strike called by the parties and communist rebels began two weeks ago. Protesters have filled the streets daily, leaving the country paralyzed, stores emptied of goods and the situation dangerously volatile. Security forces firing at protesters have killed at least 14, and wounded many more.