Security forces armed with sweeping new powers arrested dozens more people today, and police warned journalists to show "restraint" in their reporting during the second day of South Africa's declared state of emergency.

No official tally of the number or names of the new detainees was given, but a spokesman for the Detainees' Parents Support Committee said tonight that about 200 persons had been arrested today in addition to the 113 that police said they had detained yesterday.

More than 100 were held in and around the Johannesburg area, the spokesman said, and slightly fewer in eastern Cape Province. Other unofficial sources gave similar tallies.

Five more persons were killed in violence in black townships, according to police, two of them last night and three more today. Police reported more than a dozen gasoline bombings and stonings around the country and said security forces used tear gas, birdshot and rubber bullets to disperse rioters.

The country's top policeman, Commissioner of Police Johan P. Coetzee, told South African news editors at a meeting here this morning to "scale down information connected to the unrest" that has claimed about 450 lives in black townships during the past 10 months.

He later warned foreign journalists at a separate briefing that those who published the names of political detainees before they were revealed by the police could face criminal charges.

But Coetzee stopped short of invoking the emergency proclamation's broad censorship provisions over the press "at this particular stage." South African President Pieter W. Botha has designated 36 districts, including the cities of Johannesburg and Port Elizabeth, as emergency areas, and the white-minority government has the power to impose full censorship over all news from those areas.

In a move apparently designed to assuage criticism, Coetzee acceded to the request of the South African editors that police release daily the names and addresses of those detained under the proclamation. But none of those names had been released as of tonight.

Nonetheless, the identities of some of those allegedly detained today became public. Among them were:

*Four black church leaders who are prominent critics of the apartheid system of segregation and who live in or around Port Elizabeth in the eastern Cape, scene of some of the worst violence in recent months. The Johannesburg Star identified three of the churchmen as the Revs. de Villiers Soga and Samson Daba, both Anglicans, and a Methodist pastor, the Rev. Hamilton Dandala.

*At least nine other eastern Cape activists associated with the opposition United Democratic Front, which has led economic boycotts of white businesses in Port Elizabeth and other eastern Cape communities. The British Broadcasting Corp. reported that Derrick Swartz, a leading UDF spokesman in the region, was one of the detainees.

*At least 10 officials of the national UDF office in Johannesburg.

*A prominent Asian civil rights lawyer, Priscilla Jana, who was picked up by police this afternoon en route from Jan Smuts Airport outside Johannesburg while returning from a civil rights conference of the American Bar Association in Washington, according to family members. She was released later.

It was unclear whether the police total of 113 announced yesterday included 41 activists who were detained after police took custody of the two buses in which they were returning from a funeral Saturday for four black activists in the eastern Cape town of Cradock. According to The Associated Press, the detainees included Auret van Heerden, a former university student leader who tried unsuccessfully to sue police for damages last year, alleging that he had been tortured in a previous detention episode.

The emergency proclamation empowers the country's 40,000-member police force as well as the Army to arrest anyone in the designated areas without a warrant for indefinite detention. It also allows them to seize property and close down opposition groups without judicial review.

Coetzee told the meeting of South African newspaper editors, "You should handle this abnormal situation with the greatest care and circumspection. The emphasis must not be on the unrest until we have normalized the situation."

He later told foreign journalists that deputy police commissioners in the 36 designated districts could cordon off areas, declare curfews and prevent access by journalists "at their own discretion."

But he added that "there is no blanket instruction from police headquarters to inhibit the foreign press in any way. We will really endeavor not to be too cumbersome."

Nonetheless, Coetzee said reporters could be asked to reveal the names of sources who give them information about detainees. These sources could be charged with violating the emergency regulations.

Police officials have been angered in recent weeks by various reports in local newspapers of police brutality in townships near Johannesburg. Coetzee said police had collected affidavits from "people who have been quoted in the press as having said certain things who have consequently denied having ever said that allegation."

He said police had compiled evidence that unnamed journalists "have asked young blacks to stone the police to test the reaction of the police in certain areas." Other security sources have accused foreign television crews and photographers of provoking incidents.

A spokesman for the British-based UPITN television news service said a camera crew had been held by police today for 90 minutes and their film confiscated in the East Rand township of Duduza.

Reaction in the white community to the emergency declaration generally has been low-key. Spokesmen for business groups that generally have been critical of the pace of political reform here did not oppose the measures but warned that they must be accompanied by greater efforts to negotiate with blacks.