South African security forces arrested 113 persons today as the government began implementing the broad crackdown on political unrest announced last night by President Pieter W. Botha. Four more black deaths were reported.

Citing the terms of Botha's declaration of emergency powers, police refused to release the names of those detained or to provide details about the arrests except to say that they took place in the 36 magisterial districts designated by Botha's order.

A spokesman for the Detainee Parents' Support Committee said 22 persons were arrested in Johannesburg this morning. He said they had been aboard a bus returning from the funeral yesterday of four black activists in the eastern Cape Province town of Cradock. A police spokesman later confirmed that the bus had been held at police headquarters here.

Police officials said they would meet Monday with representatives of the South African press to establish a mechanism for censoring all information about the designated areas.

Commissioner of Police Johan P. Coetzee told the state-run television broadcasting company tonight that the government would not seek to inhibit "the free flow of information." But he said news accounts from the affected districts would be "properly validated and properly controlled" by the authorities, and he warned against "dramatized versions, slanted truths and half-truths -- these will obviously not be allowed."

Those districts are located in the central Transvaal and eastern Cape regions, some of whose black townships have been in a state of virtual siege in recent months because of clashes between protesters and security forces.

Botha said the emergency order, the first in 25 years, was "to ensure that a normal community life is reestablished" in those areas. But opponents said they feared that the declaration would mean a return to the tactics of an earlier era.

Nobel Peace Prize laureate Bishop Desmond Tutu called the emergency order "a typical response of a repressive and unjust administration that does not know how to deal with dissent."

Violence continued despite the new measures. Police reported four major incidents in the town of Parys southwest of Johannesburg, but not within the restricted areas, in which they said three black males died and five others were injured.

State-run television reported that one man was killed in clashes with police in a black township in the eastern Cape. There were also unconfirmed reports of clashes last night in the township of KwaThema east of Johannesburg.

Mourners in a black township outside the city of Witbank threw rocks at police vehicles this afternoon and were dispersed by tear gas. A white man reportedly escaped death narrowly when a mob attacked and burned his car.

The incidents occurred after the funeral today of a 23-year-old woman who was shot to death during rioting last week. Witbank, which is in the eastern Transvaal, is not one of the emergency areas.

The decree is an attempt to cap 10 months of unrest in which at least 443 persons have died, all but one of them black.

Officials in recent months have sought to ease some of the harsher restrictions of the longstanding system of rigid legal segregation known as apartheid. They also have created local governing authorities designed to give urban blacks a limited measure of local self-rule.

But the councils, whose elections were boycotted by the majority of blacks, have become, along with black police, the focus of grievances and the targets of government opponents.

Dozens of councilmen have been compelled to resign and only five of the 32 councils established by Pretoria are still functioning, according to a recent study. Several local officials have been killed, and black police officers have been forced to flee their homes in many townships.

The violence also has been fueled by a series of factors, including discontent with housing and schooling in the townships, an economic recession and resulting high unemployment, and the existence of a growing network of black community organizations and trade unions whose members have mobilized to express grievances.

Analysts cite several recent events that underscored the increasing scope and intensity of the violence and may have helped move the government to adopt the emergency measures:

*The upsurge in unrest in the nearby East Rand area, where more than two dozen persons have died during the past month.

*Last week's confrontation between rampaging youths and riot police in Soweto, the country's largest black urban center, which had remained relatively calm during the first nine months of trouble.

*Signs that the violence was spilling over into white areas in Johannesburg suburbs that border black townships.

*Indications that the outlawed African National Congress, the main resistance group fighting white rule, was finding the East Rand townships fertile ground for recruitment and was attempting to smuggle weapons into the area.

Although security forces in South Africa generally enjoy widespread legal powers, the emergency declaration gives the police and Army even more sweeping authority to deal with any sign of unrest.

South African law generally requires written warrants before property can be searched and seized. It also requires a ministerial order before a person can be detained without charge. These acts can be subject to judicial review.

But under the emergency powers act, police can detain persons for 14 days and hold them indefinitely after that period with ministerial approval. Political or other organizations can be suspended without notice and property can be searched and seized without warrant. The security forces also are indemnified against judicial review for any actions they may take.

Some South African newspapers, especially the daily Johannesburg Star and the weekly City Press, have angered officials with coverage of township unrest and allegations of police brutality in recent weeks. The censorship provisions of the order give the government the power to cut off any or all news from the designated areas.

Despite the new measures, the scenes at some of the affected areas were eerily calm today. A tour of Duduza and KwaThema, two of the East Rand townships that figured in recent violence, showed residents engaged in their usual Sunday morning activities, strolling and shopping and returning from church. There was only a token police presence, with no roadblocks or other unusual activity.

Black policemen in Duduza, where a woman was burned to death yesterday by a mob that branded her a police informer, could be seen lounging outdoors within the barricaded perimeter of the charred community hall that they have turned into a fortified headquarters. Their laundry flapped on the barbed wire of the enclosure.