Black rioters opened fire on police for the first time outside the Cape Town area, wounding two officers last night, in an incident marking a distinct escalation in South Africa's political strife.

Fresh violence was reported today as South African authorities began to crack down on reporters as part of its reaction to 14 months of turmoil.

The police officers were wounded in the country town of Beaufort West, in central Cape Province, after a day of clashes in which a mixed-race man was killed and 10 blacks were wounded by police gunfire.

A warning today in the mass-circulation Afrikaans-language newspaper Rapport that "strong action" would be taken against the press soon was followed by the first arrest of a Cape Town reporter under emergency regulations that were extended into the area yesterday. The reporter was held for six hours after entering a mixed-race township to report on a meeting planned by a group of activists. Four foreign journalists were detained by authorities in Cape Town on Friday for more than three hours before they were released without charges.

There has been a buildup of criticism of the role of the press in recent weeks, and the foreign press has been accused of presenting a distorted image of unrest in South Africa and thereby contributing to the country's financial crisis.

Tonight, authorities announced sweeping new regulations banning all meetings by 102 antiapartheid organizations in the area, where two months of violence have resulted in about 70 deaths.

Four more blacks were shot dead by the police in townships of Cape Province, and there were reports of clashes from at least a dozen other centers last night and today.

The trouble in Beaufort West began Friday after an inquest verdict by a magistrate, who found that the police had acted in self-defense when they shot a local black political leader, Mandlenkosi Kratshi, last January.

Police fired tear gas at a crowd that demonstrated angrily against the verdict. There were further clashes yesterday when troops and police surrounded Beaufort West's black townships, where about 6,000 people live, and began house-to-house searches.

Some blacks contend that they were hit with horsewhips during the searches.

A reporter who visited the area said rioting broke out in the township streets, and angry youths set up at least 20 burning barricades. The clashes reached a climax last night, when a crowd of mixed-race and black people confronted the police on a soccer field.

As the police opened fire with tear gas, rubber bullets and shotguns, wounding a number of persons, some shots rang out from the crowd, and two policemen were wounded. A third police officer was injured when a rock struck him on the head.

Although there have been a number of incidents in the segregated townships around Cape Town recently in which black and mixed-race rioters shot back at the police, this is the first time that it has happened outside that troubled metropolitan area. Such intense resistance to police action in a relatively small town is unusual.

Reports in both English- and Afrikaans-language newspapers have alleged that television crews in particular have instigated acts of violence for their cameras. Foreign teams have denied this.

In the most sweeping allegations so far, which seasoned observers saw as a precursor of official action, Rapport quoted unnamed "top-level police sources" today as saying that "hostile-minded media people, especially foreign correspondents," had become the main factor obstructing the police in their campaign against the unrest.

"Strong action will be taken against these people within the next few weeks," the newspaper added, in a report that dominated its front page.

For the past several weeks, the authorities have been tightening up on coverage of the unrest by ordering townships closed to reporters. Several reporters have been summarily arrested for brief periods in unrest areas, and videotape of television cameramen has been confiscated. Yesterday the authorities banned all journalists from Soweto, the country's largest urban center, until further notice.

Today, a local reporter, Peter Dennehy of The Cape Times, became the first journalist to be arrested under the emergency regulations, which give sweeping powers to individual police officers.

Dennehy was arrested when he entered a mixed-race township outside Cape Town to report on a meeting to be held by a group of activists. He said in a telephone interview tonight that he was first told he would be imprisoned for 14 days without charges, but he was released after six hours and warned to appear in court Monday to face a charge of attending an illegal gathering.

In a separate development today, the heads of 52 U.S. corporations operating in South Africa placed a full-page advertisement in a local newspaper pledging their support for an antiapartheid statement made a month ago by 91 South African corporations.

The group, calling itself the "U.S. Corporate Council on South Africa," said that it was pledged to play an active role in working for the abolition of statutory discrimination, negotiations for power-sharing with acknowledged black leaders, granting full citizenship rights to blacks and restoring the rule of law.

The original declaration, issued Sept. 29, contained the names of many of South Africa's biggest companies, but despite its relatively bland phrasing it was shunned by nearly all those controlled by members of the dominant Afrikaner community who are close to the government, thus making little political impact.