Two more European missionaries: both West Germans, have been killed in a Rhodesian war zone, Catholic church official reported yesterday.

The Rev. Horst Ulbrich, a spokesman for German Jesuits operating here, said the two Jesuits apparently were killed Tuesday night at the remote St. Rupert's mission, 90 miles west of Salisbury.

St. Rupert's is within the Magonde tribal reservation bordering on white-owned farmland and is about 20 miles from the Sanwati mission where an American Southern Baptist was bayonetted to death 13 days ago.

Last Friday, 12 Briton missionairies and members of their families were hacked and clubbed to death near Rhodesia's eastern border with Mozambique.

The dead Germans were identified as Gregor Richert, 42, and Bernhard of the mission. Lisson had worked in Rhodesia for more than 40 years, and Richert came here about 10 years ago. Lisson, 69, the only white employees Another Jesuit spokesman said the two men were shot, reportedly by three black gunmen.

The German Jesuit order runs missions across a vast stretch of north and central Rhodesia. Ulbrich said there are no plans to remove about 30 other white missionairies base in isolated missions.

Meanwhile, U.S. and British peace envoys Stephen Low and John Graham left Salisbury after a second visit aimed at mustering support for an all-parties Rhodesian settlement conference.

Low, the U.S. ambassador to Zambia, and Graham, a British Foreign Office undersecretary, appeared to have made no headway to diminish the opposition of the four leaders of Rhodesia's multiracial transitional administration to talks including guerrilla leaders in exile.

[In Lusaka, Zambia, Rhodesian guerillan leader Joshua Nkomo confirmed that one of his key commanders, Alfred N. Mangena, 33, was killed by a land mine near the Rhodesian border. No details were offered.]