As sectarian violence triggered by the assassination of prime minister Indira Gandhi began to ebb today, the government of her successor and son, Rajiv, was confronted by the potentially explosive problem of ensuring the safety of tens of thousands of Sikh refugees who are afraid to return to their homes.

Sikhs who found sanctuary from Hindu mob violence in makeshift relief camps or in private homes said they are demanding security guarantees from the Army before they return to their religiously mixed neighborhoods in riot-torn New Delhi.

The government confirmed today that 458 persons had been killed here during the past four days, while unofficial death tolls are as high as 600 dead in the capital and 1,000 throughout the country.

Some homeless Sikhs said in interviews in the camps that they wanted to leave the capital for the heavily Sikh-majority state of Punjab but were afraid that they would fall victim to Hindu mobs that have attacked passenger trains and killed scores of Sikhs. The carnage is reminiscent of the Hindu-Moslem killings that followed partition of the Indian Subcontinent into India and Pakistan in 1947.

The government offered assurances today to the largely skeptical Sikh community that normalcy would be restored soon and that most Sikhs would be able to leave the refugee centers and return to a normal life.

Madan M.K. Wali, who was appointed lieutenant governor, or chief administrator, of this capital of 6 million today, said at a news conference, "My endeavor is to see that this orgy of madness . . . is put to a stop."

As the dimensions of the massacres of Sikhs in reprisal for the assassination of Indira Gandhi by two Sikh security guards started to emerge yesterday, police stations in Sikh neighborhoods throughout New Delhi began to fill with Sikhs seeking protection or having no place to live because their homes had been burned by Hindu mobs.

Later in the evening, authorities shifted many of them to three hastily established refugee camps in government schools and five smaller "rescue camps" set up in government-owned buildings.

Wali said that 20,000 refugees are being housed in the camps and another 4,000 in the Sham Lal College, and that others are still seeking shelter in police stations. Still more are hiding in Sikh temples.

Wali conceded that the figures fail to account for Sikhs believed to have fled to homes of friends and relatives in the city.

"The decision is that those who want to go back to their homes should go back . . . . We will not discourage them. But before we allow them to go back, we want to be sure that there will be no threat to them," Wali said.

When pressed on how long the refugees would remain in the camps, Wali replied, "Our belief is that they will not stay in these camps too long. When confidence comes, they will leave, in a matter of days."

Many refugees interviewed had a different perspective.

At the Ludlow Castle government model school in old Delhi's Raj Niwas area, Harbhajan Singh, 24, a civil engineer, said, "We won't stay in Delhi. It's impossible to stay. These people behaved like butchers. I'm not going back to my home." Singh said he wanted to go to Punjab, where his father lived until 1950, but that he was afraid to travel by train.

"The second night of rioting , trains came in packed with corpses. It was worse than 1947. Every Sikh was butchered, or if he wasn't butchered, his hair and beard were cut off. If we ride the train, the Army must provide security," he said.

The courtyard of the school was filled to overflowing with Sikh refugees, many of them sitting under sparse trees seeking shade and still looking dazed by the violence that swept through their neighborhoods.

Some displayed knife wounds and dark welts from beatings with wooden staves and cricket bats, and one had fingers on one hand cut off.

Suvinder Singh, 24, who makes farm tools, displayed dark bruises from a beating and ragged remnants of a beard and head hair that he said were cut off by 25 Hindus who broke into his home.

A mandatory ritual of the Sikh religion is to wear unshorn beards and hair, and devout Sikhs regard the loss of either as a personal disgrace. Singh said the mob found him hiding under a cot on the third floor of his home, and that after he pleaded with them to spare his life, they cut his hair and beat him.

"I can't go back to my home. They are all after me. I will go to Patiala in Punjab . We will all go to Punjab," Suvinder Singh said, referring to his mother, father and sister, all of whom he said were beaten during the Thursday night attack.

When asked if he would travel to Punjab by train, he replied by shrugging his shoulders and saying, "On the way to Punjab is Haryana. I'm afraid the government won't do anything to protect us." Haryana is a predominantly Hindu state.

Like many Sikh refugees interviewed, Suvinder Singh blamed the government for the anti-Sikh rampages, saying the police deliberately pulled back to allow Hindus to vent their outrage.

"Look how they arranged the Army in Delhi today," he said, referring to the deployment of 21,000 troops and numerous tanks and armored personnel carriers in the city. "Just like they arranged the Army, they could have stopped the massacres Wednesday."

Balbir Singh, a tourist-bus operator from Punjab, cited the virtual martial law imposed in Punjab preceding the June 5 Army assault on the Golden Temple in Amritsar, saying, "If they can put the whole of Punjab under the protection of the Army, why can't they do it here?"

At the Guru Tegh Bahadur Sikh temple in the normally teeming Chandni Chowk bazaar in old Delhi, three Army tanks and scores of soldiers with their rifles at the ready guarded a now-deserted street as Simrit Singh Grewal, a retired Army captain, talked about the assassination and the depths of bitterness that it and its aftermath have created between the Sikh and Hindu communities.

The assassination "was not the fault of all the [Sikh] people, but all the people are suffering because of it. This disturbance came like a storm," said Grewal, one of about 300 Sikhs who have sought shelter in the imposing and ornate temple.

Grewal said that as long as the Army is encamped outside, he will feel safe, but, he added, "What will happen when they leave? I feel safe now, but what of later?"

Thursday night, Wali, who was then India's home secretary, said at a press conference that only two persons had been killed in New Delhi. This was to the astonishment of many reporters covering the rioting who had confirmed many killings.

Today, in his capacity as head of the city government, Wali said that violence had been "unprecedented," but that the capital quickly was returning to normal.

"Delhi has never seen such a thing before. Delhi is used to seeing big crowds, big agitations, and the odd riot here and there. But the last two days have been totally unprecdented."

Wali said that Sikhs would probably be unwilling to leave the safety of police-guarded refugee camps until they regain confidence in the authorities, and that the government was taking steps in that direction, including the deployment of the Army and the arrest of 1,800 persons for rioting.