An audience of whites booed and heckled Prime Minister Ian Smith last night when he said he had agreed to bring blacks into the government because it was the best deal that could be expected after six years of guerrilla war.

"Rubbish!" some members of the audience shouted. "How many more have to die" others yelled.

In an interview earlier with the South African Press Association, the prime minister urged the United States to lift economic sanctions against Rhodesia as a first step toward ending the guerrilla war.

Smith, who jointly heads a transition government with three black leaders, has promised black majority rule by the beginning of the year.

"We are fighting for our lives, for our very existence." Smith told the restive audience of about 300 in an affluent suburb. He said it is increadible for some Rhodesians to believe the country can live in isolation from the rest of the world.

That remark also drew catcalls and comments from the audience, and Smith appeared rankled when someone reminded him that he once said "never in a thousand years" would blacks rule Rhodesia.

Smith's call to lift economic sanctions came in the face of a new bid to get U.S. Senate approval for a six - month moratorium on sanctions against Rhodesia.

Meanwhile, students and police reported that a group of young whites had attacked black students at the University of Rhodesia Monday night.