Pratab Singh, standing beside a dried pool of blood and holding a blue turban now stained with red, told how his 21-year-old son had been killed there on the roof of his apartment building yesterday by a shot from a policeman's rifle.

"We only lost our possessions in '84, but we came here and we have lost our son," he said. Riot police patrolled the narrow streets four stories below in an effort to prevent a resumption of the Hindu-Sikh violence that took at least six lives yesterday.

The housing was built for victims of the 1984 rioting that cost about 2,700 lives, mostly of Sikhs, after the assassination of prime minister Indira Gandhi by Sikh extremists.

This neighborhood, known as Tilak Nagar, is a tinderbox where mutually antagonistic communities are mixed and live along narrow, twisting streets.

As Bratab Singh's wife cried beside him, he told how their son had gone to the rooftop after lunch with a glass of water when the shot rang out. When the father reached the scene, he took off his son's turban, and the blood flowed from the back of the head. The couple's clothing still bore the stains of the son's blood, like badges of mourning. They said the son had done nothing to provoke the police fire, but Arun Bhagat, commander of the local police, said his men opened fire because "it was a riot situation."

The riot began when Hindu refugees from the Punjab, housed in a temple that backs up against that of the Sikhs, gathered to protest the killing of 14 Hindus on Friday aboard a bus in Punjab and to demand protection.

Dharan Pal, a Hindu, said he had come to Delhi from the Punjab -- the state where Sikhs predominate -- after his brother had been shot to death and he began receiving threatening letters there. Now living with about 100 others inside the temple compound, Pal said they had told the police, "We want education for our children. We want safety."

He said the police had promised to send someone to talk with them, but no one came, and when they persisted the police threatened to arrest them.

Earlier, the head of the neighboring Sikh temple had said that scores of Hindus had poured across the wall separating the two compounds and ransacked the building, burning the Sikh holy book as it lay open on the altar.

Pal, however, gave a different version of the day's events, saying the Sikhs had "cussed us" from their temple but that "no one from our camp went over." He said no one in Delhi would listen to their complaints. "They only say to go back. When there is peace, we will go. Now they only kill Hindu people. Why do they say go back? Where to go? to Punjab?"

Others on the earthen floor of the temple told of harassment and intimidation in Punjab before they fled for Delhi. Authorities estimate that several thousand Hindus have left Punjab in recent weeks as Sikh separatist militants have turned their violence upon Hindus. Earlier, the targets had been more moderate co-religionists.

Sikhs in the temple next door charged that the new arrivals include adherents of militant Hindu organizations, but the refugees said they have taken no part in the violence. Jaspal Singh, the area's elected member of the Delhi metropolitan council, came to the refugee center this afternoon, pleading with the Hindus not to let the trouble of the Punjab continue to spill over here.

He said all elected officials of the ruling Congress Party had been ordered by Prime Minister Rajiv Gandhi to get out on the streets and calm tensions.

Jaspal Singh, a Sikh, said he had given funds to the Punjab refugees and the Sikh temple "from my own pocket" to try to ease grievances harbored by each. Later, outside the refugee center, he noted that the area had remained quiet in 1984, while much of the rest of Delhi had burned. It was after the arrival of the Hindu refugees that tensions had begun to rise.

It remains unclear who started yesterday's violence and why. Clearly, as word spread of the sacking of the Sikh's temple and burning of the holy book, Sikhs tried to defend the temple. They were repulsed by police, who soon began to clash also with the Hindu crowds.

It was then that firing began, ultimately leaving at least four persons dead of gunshot wounds and a fifth from stabbing. A sixth died of gunshot wounds overnight in a hospital.

Today, the city was calm under curfew. In Punjab, however, the Press Trust of India reported that Sikh extremists hacked a Hindu priest and a shopkeeper to death and security forces shot dead one of the assailants.

In unrelated violence in West Bengal, nine persons were reported killed when police in the town of Kalimpong fired on Gurkha separatists who attacked them with rocks and knives. A curfew was imposed.