JOHANNESBURG, SEPT. 17 -- Police today caught South Africa's most-wanted white man, a right-wing extremist accused in several bombings, a top official said.

Piet "Shoot" Rudolph was arrested in a car in Pretoria, Law and Order Minister Adriaan Vlok said.

The capture came as police announced a major effort to stem black factional fighting and to pursue what President Frederik W. de Klerk called a "third force" fomenting that violence. African National Congress leader Nelson Mandela has said that force consists of white right-wing extremists.

Rudolph, also wanted for arms theft, had three guns with him, police said. The self-confessed pro-apartheid guerrilla, who had a $19,000 price on his head, had been on the run for four months.

While a fugitive, Rudolph telephoned the Pretoria News and claimed responsibility for the theft of arms and ammunition from air force headquarters in April and bomb attacks on offices of the ruling National Party and two newspapers.

He said the bombs were planted at his command by a group called the Order of the Boer People. White right-wingers descended from early Dutch settlers call themselves Boers after 19th-century soldier-farmers.

In a video delivered to the News, Rudolph declared war on the government of de Klerk, who has promised to dismantle apartheid and give the nation's black majority a share of political power. When de Klerk announced initial changes in February he unleashed a flood of protest from right-wingers, who accused him of selling out the white minority.

Rudolph is a former Pretoria city council member and deputy leader of the far-right Boerestaat Party.