Prime Minister Robert Mugabe has sharply criticized three U.S. senators for questioning the treatment of three imprisoned Zimbabwean Air Force officers who are alleged to have been tortured. The officers are white, and Mugabe suggested that the senators were interested in the case because of racial reasons.

In an unusual public move, the government today published in the Herald, the country's main newspaper, the text of a letter to Mugabe from Republicans Mark Hatfield of Oregon and Paul Laxalt of Nevada and Democrat Thomas Eagleton of Missouri, along with the response of the prime minister, signed by Charles Utete, his permanent secretary. The senators, members of the Foreign Relations Committee, which has approved $150 million in aid to Zimbabwe in the past two years, visited here in October.

The surprisingly sharp letter was the first public response by the government to the allegations of torture made in September and widely reported overseas.

The senators expressed concern about reports of torture of the officers, detained after the sabotage of 13 warplanes in July, although they acknowledged, "We have no direct personal knowledge of the facts."

"If this is indeed so," Mugabe said, "why then do you protest. . . ? Is it to be supposed that it never occurred to you to suspect that, unlike yourselves, the Zimbabwean government might conceivably have such a 'direct, personal knowledge' of the facts of this matter as to warrant the arrest of the three men?"

Mugabe did not confirm or deny the allegations, saying comment would be withheld pending disposition of the case in court. He accused the senators of "politicization of the issue" by moving it "from the judicial into the political arena."

Implying that their interest was racial, Mugabe said, "A number of black suspects are also under arrest for the same reason. Yet the latter do not appear to have attracted your attention. What makes for this selectivity of observation and concern?" he asked, then added, "Needless to say, our policies and actions have nothing in common with racialism."

A spokesman for Sen. Eagleton said Mugabe's response had not yet been received. He added that in no correspondence had the senators raised the issue of, or mentioned, the race of the officers.

A white minority ruled Zimbabwe until independence from Britain in 1980. Mugabe was a leader in the successful guerrilla war, during which his forces charged mistreatment of captives by the whites.