A group of U.S. congressmen joined yesterday in statements strongly condemning the South African government's proposal to abolish the black squatters' community of Crossroads, near Capetown.

Terming the plan "as insensitive, cruel and brutal an action as the South African government could take," they renewed an earlier appeal to President Carter to "convey your concern for this most recent atrocity."

On Aug. 31, 15 members of the House signed the letter to Carter, calling themselves the Congressional Ad Hoc Monitoring Group.

"We believe that although it may be too late for the United States to intervene in the situation, it is important for the United States to respond to this atrocity through high-level expressions of concern," the letter said.

South Aftican officials have announced their intention to move about 20,000 people out of the Crossroads township, which was established in 1975 as a black squatters' community. The legislators said they said they were told that many of the residents of the area intended to defy government efforts to forcibly remove them to other locations.

In a news conference, members of the group noted that Tuesday was the first anniversary of the death of South African black leader Steve Biko, sayings that "serves as a tragic reminder of our responsibility to focus international attention on the oppressive acts by governments, no matter where they may be."