Police detained a white U.S. diplomat and a black American poet for more than an hour today after they entered racially tense Soweto township without permits.

The South African township, home of 1 million blacks, has been the scene of student disturbances, including scattered incident today in which more than a thousand students took part. Police said two bakery vans were attacked and robbed. One van was set on fire.

Michael Harper, director of the creative writing department at Brown University, and William Jacobsen, head of the Johannesburg office of the U.S. Information Service, said they were picked up outside a high school where Harper had given a poetry reading.

Jacobsen said they were released after being questioned by the white police chief.

"He asked for our permits and I said we didn't have any and I took full responsibility," said Jacobsen. "I told him the USIS had a reading room in Soweto for 13 months - I was sure he was aware of that - and said we hadn't had any problem before."

In another development, the Automobile Association of South Africa said black drivers will finally be able to become members next month, two years after a decision to admit them has taken.

The association said that membership would be open to all races from July 1.