n the widest police action ever against black labor union members, 205 people from three different unions were detained Sunday night in East London as they returned home from a meeting in buses, the Rand Daily Mail newspaper reported today.

The union members, including many skilled workers from factories in East London, were arrested by police in the homeland of Ciskei and are being held under a Ciskei security law that allows for three months detention without trial.

Ciskei is one of the 10 black homelands set up under South Africa's apartheid system. It is due to become independent in December.

East London is a major industrial and port town on the Indian Ocean coast. But due to gerrymandering of Ciskei boundaries, it is not included in the homeland and remains in white-controlled South Africa.

Most workers in East London factories, however, live in the Mdantsane, the nearby black township that is inside Ciskei.

East London has been one of the fastest-growing centers of a militant black labor movement. One union based here claims between 16,000 and 23,000 members. This work force, led by unionists who are not sympathetic to the apartheid system and the imminent independence of Ciskei, are seen to pose a threat to the Ciskei government, and most observers believe major clashes could follow independence.

Today's action follows the disclosure in Parliament last month that the South African security police had drawn up a contingency plan for "breaking" one of the East London-based unions, the South African Allied Workers' Union (SAAWU). Police Minister Louis le Grange acknowledged police had distributed the document to white company managers to solicit their support.

South African police have trained and continue to work closely with the Ciskei police.

The arrests represent the second major clampdown on trade unionists by the Ciskei authorities this year. Last May, at least 57 trade union leaders and organizers were detained for indefinite periods.

The union members arrested belonged to SAAWU, the General Workers' Union (GWU) and the African Food and Canning Workers union. Police stopped the buses headed to Mdantsane from East London and ordered them to the police station, the South African Press Association reported.

Ciskei police are investigating charges against the unionists under the Riotous Assemblies Act, according to Ciskei Police Chief Charles Sebe. Sebe told one reporter the workers had been detained after they had been "singing freedom songs, denouncing the present system of government, upholding a Mandela-type government and waving black power salutes."

Nelson Mandela is the former president of a banned guerrilla movement, the African National Congress. He is serving a life sentence for sabotage.

SAAWU President Thozamile Gqweta described the arrests as "outrageous." "There is nothing illegal about singing freedom songs--this is clearly another crackdown on unionists," he said.