Two white Rhodesian airmen were killed when their plane crashed in the eastern operational area stretching along the country's tense 600-mile border with Mozambique, military authorities reported here today.

They did not say whether the plane was shot down or crashed accidentally, nor did they give the time or exact location of the crash. A brief announcement said only that the aircraft crashed during "an operational sortie" in the area along the border with Mozambique, main crossing point for black nationalist guerrillas battling the Rhodesian white-minority government.

[In London, meanwhile, the Observer reported that the Rhodesian Special Branch had arrested four officials of the Catholic Commission for Justice and Peace in Salisbury in an apparent attempt to suppress a report alleging that the Rhodesian army is continuing to torture black civilians." The report is to be published in London this week by the Catholic Institute for International Relations.]

Apart from the crash in which the two airmen died Rhodesian military authorities reported that 17 nationalists guerrillas had been killed in recent fighting.

They also said guerrillas using mortars and small arms attacked two Rhodesian farms in the west and southwest and accused Mozambican troops of aiding a guerrilla attack on two stores near the Mozambique border.

A military communique said one guerrilla was killed by a farmer but mentioned no civilian or other Rhodesian casualties military casualties.

Michael Holmes of the London Observer reported that:

The Catholic commission officials arrested are its chairman, John Deary; its organizing secretary, Brother Arthur Dupuis: its press secretary, Sister Janice McLaughlin, and an executive member, Father Dieter Scholz, who was ordered last month to leave Rhodesis by mid-September.

They are to be charged under the Law and Order (Maintenance) Act and the Official Secrets Act. Sister Janice, it was reported, is being held at a prison outside Salisbury, while the others have been released on bail.

The commission has published two earlier reportd on alleged Rhodesian army brutality and the conduct of the five-year guerrilla war. Last March, its president, the Catholic Bishop of Umtali, the Right Rev. Donal Lamont, was deported.

Reports of torture by the military forces "continue to be the rule rather than the exception," the commission says. It claims that the army and police are "hated and feared by the people" - a point made by the leaders of the Patriotic Front, who are insisting that the Rhodesian forces be disbanded under any settlement.

School children, the report says, are often brutally questioned. One method, according to a headmaster, is to cover the suspect's face with a towel, which is then saturated with water to simulate drowning. Priests and sisters have also been beaten during questioning, the commission claims.

Over half a million tribespeople, double the official figure, are now held in 'protected' villages. it says.

Protected villages - fenced and patrolled hamlets in which blacks have been regrouped - were first introduced in 1973 in an attempt to isolate tribespeople from guerillas.

The commission report says there are now 203 protected villages, mainly in northeast and southeast Rhodesia, corresponding to the main operational areas of the war, but others are being established in the northwest.

On the basis of first-hand reports, mainly from missionaries, the commission estimates that there are 580,000 people who have been compulsorily removed.