Nepal's opposition parties said Sunday that a nationwide general strike and anti-monarchy protests would continue indefinitely, as the government accused Maoist militants of infiltrating the demonstrations and shooting at police. Police, meanwhile, fired rubber bullets and tear gas during clashes with protesters in the capital, Katmandu on Sunday, television footage showed, as thousands defied curfews and short-at-sight orders and marched in city streets to demand a return to democracy. Three people have died in police firings in other towns. The demonstrations are part of a four-day strike by the country's seven main political parties, being held for the first time with the support of the armed communist militants, which was to end Sunday. But representatives of the seven parties met amid the curfew and declared in a statement that, "The nationwide general strike and protests will continue until further notice." The government had justified its crackdown on the strike saying it had intelligence, partly based on the interrogation of arrested militants, that the rebels had infiltrated into the protesters and would wage attacks against government targets. Home Minister Kamal Thapa told a news conference in Katmandu that those fears had proved correct: police had arrested among the hundreds of protesters four men, who have previously been identified as Maoist rebels and were wanted by police. He also alleged that militants pretending to be pro-democracy protesters had fired at security forces with guns. Thapa did not say whether there had been any injuries. Rebel chief Prachanda, whose organization is backing the ongoing anti-monarchy protest campaign, has promised not to carry out attacks in Katmandu. "The terrorists have fired despite their pledge not to carry out violence in the capital," Thapa said. He said "the security forces have recovered cartridges at Gangabu" neighborhood on the northwest edge of Katmandu where a curfew was not imposed but several protests were reported. Meanwhile, witnesses and Nepali media also reported protests in dozens of other towns and cities. Thousands defied a curfew and shoot-on-sight orders and marched in at least four different parts of Katmandu, demanding that King Gyanendra step down. Youths marched in the streets and threw stones at police before being forced back by tear gas. The private Kantipur Television showed footage of police shooting rubber-coated bullets, hitting at least one protester. A group of demonstrators marching from a suburb into Katmandu was blocked by a line of policemen, and minor scuffles broke out between the two sides, a police official at the scene said over the telephone. The police, however, managed to stop the rally from moving inside the city limits, the official said, asking not to be named because of the political climate. More than 2,000 people rallied in the southern town Bharatpur, angered by the death of demonstrator shot by security forces a day earlier. On Saturday, roughly 25,000 protesters set fire to at least a half-dozen government offices and forced riot police to retreat from the main square of the town, which is 140 kilometers (90 miles) southwest of Katmandu. A second protester was fatally shot Saturday in Pokhara, about 200 kilometers (125 miles) west of Katmandu. A third died when security forces opened fire on demonstrators in Banepa, 32 kilometers (20 miles) east of Katmandu, where a large crowd of protesters was shouting slogans and hurling stones at security forces, a local official said. He spoke on condition of anonymity because he is not authorized to talk to the media. Sunday was the last day of a four-day general strike called by an alliance of the country's seven main political parties and backed by Maoist rebels, who want to replace the king with a communist state. The parties and the rebels formed a loose alliance in December, and this marked the first opposition strike with the Maoists' backing. Saturday was the 16th anniversary of the introduction of democracy in Nepal, an experiment that collapsed last year when Gyanendra took control of the government and promised to crush the Maoist rebellion and hold elections within three years. Many Nepalis at first welcomed the king's move. But the insurgency since has worsened and the economy has faltered, fueling the discontent that has been on display in recent days as thousands of workers, professionals and business people have for the first time joined students and political activists at protests. Apart from Saturday's shootings, the government has arrested more than 800 people since Wednesday. Police were seen Saturday detaining another 20 rights activists for defying the curfew. The crackdown on the opposition has prompted condemnations from the United States, Japan, the European Union and neighboring India, all of which have been critical of the king's seizure of power.