Rhodesian black nationalist leader Joshua Nkomo said yesterday he would not be pressured by military attacks into holding talks with the white-dominated Rhodesian biracial government and termed the Angle American proposal for a general peace conference "nonsense" and "humbug."

Bitter and highly emotional at a press conference at his home here, Nkomo vowed to avenge fully the death of more than 200 "noncombatant refugees" killed in an attack by Rhodesian fighter jets Thursday on one of his camps outside the Zambian capital.

Speaking before Rhodesian Prime Minister Ian Smith and his interim government agreed in Washington to attend all party talks, Nkomo said his Zimabwe African People's Union (ZAPU) would not be swayed by such raids into attending talks with Smith or the Western-proposed conference which he called all "all-party non-sense.

"If Smith thinks that way or his helpers, or the United States and Britain think this is what they can do to us, then they must be daydreaming," he said referring to the Rhodesian prime minister and the three black members of the ruling executive council in Rhodesia - Bishop Abel Muzorewa, Rev. Ndabaningi Sithole and Chief Jeremiah Chirau.

But asked specifically if we would attend a conference if Smith and his three back colleagues agreed to go, Nkomo sidestepped the issue and seemed anxious to avoid giving a clear answer.

The United States and British governments have been trying to get Rhodesia's interim government leaders and the Patriotic Front guerrilla co-leaders, Nkomo and Robert Mugabe, to meet in an all-party conference in an effort to resolve the war with a peaceful settlement.

The guerrilla war against Rhodesia has been gradually escalating in intensity since Smith unilaterally declared the former British colony independent in 1965. Under pressure from the United States and Britain Smith brought blacks into the government in March and declared that there will be nationwide elections by the end of the year. The guerrilla leaders have called the new white-dominated government a sham.

Rhodesia has about 230,000 whites and 6.7 million blacks.

The agreement of the four leaders of the Rhodesian transitional government to attend an all-party conference places both Nkomo and Mugabe in an awkward position.

Nkomo said Sept. 11 that the British-American proposed conference was "dead and buried" and that it was now "war to the finish" with the Rhodesian government. He repeated his intention yesterday of fighting it out, saying, "We mean to get that country by force and we shall get it."

Smith's government and Nkomo have now made a complete turnabout on the conference issue. Six months ago Smith was opposed to an all-party conference and Nkomo said he would attend one if certain preconditions were met. The second guerrilla leader, Mugabe, has never excluded attending an all-party conference and indicated publicly that he disagreed with Nkomo's comment that it was now "dead and buried."

The two patriotic Front leaders will now have to get together to discuss a common joint position in the light of Smith's acceptance. But if both Kaunda and Mugabe's two key backers among the "front-line" presidents, Samora Machel of Mozambique and Julius Nyerere of Tanzania, want the two nationalist leaders to go to the conference, it is likely they will agree at least to attend.

Nkomo's main backer among the so-called African Front-line presidents, Zambian President Kenneth Kaunda, is still supporting the Western initiative and, following Thursday's attack on the outskirts of his capital, may be more anxious than ever to see an all-party conference held.

So far, he has made no statement about the raid or whether Zambia will take any retaliatory measures.

Mugabe, who leads the Mozambique-based Zimbabwe African National Union (ZANU), said the earlier this month that his party would not accept any further American participation in the negotiations for a settlement of the Rhodesian dispute because Washington had allowed Smith to visit the United States and was no longer "impartial."

The issue of whether a conference will be held probably now depends heavily on the position taken by the five front-line states and Anglo-American ability to convince them it has some chance of succeeding.

Meanwhile, Nkomo took sharp issue with the Rhodesian description of the attack on Chikumbi camp, 12 miles north of here, as a "main controlling military headquarters" of his guerrilla army. He said United Nations agencies and the International Red Cross are helping convert the camp into a center for young male refugees from Rhodesia.

Several U.N. officials here confirmed this account and said Chikumbi had previously been a military camp but was no longer one. If so, it appears that Rhodesian intelligence was sat least several months old regarding the nature and use of the camp.

Meanwhile, 300 to 400 students paraded through the city and demonstrated in front of the American and British embassies in protest against the Rhodesian raid. They blamed British and American "imperalism" and yelled "Yankees go home." There was no incident and the demonstrators dispersed peacefully.

Nkomo, who heads the Zimbabwe African People's Union (ZAPU) wing of the Patriotic Front, gave reporters a detailed breakdown of casualties sustained during the Rhodesian attack.

He said 226 men were killed and 629 others wounded, 403 of them seriously enough to be hospitalized. Altogether, there were 2,948 inhabitants at the Chikumbi camp at the time of the attack, he said.

Although Rhodesian air and ground forces killed more than 1,000 refugees and guerrillas in one single raid into Mozambique last year, this is by far the highest death toll ever inflicted on those living here in Zambia at any one time.

Nkomo repeatdly stressed that all the young men in the camp were strictly "noncombantants" and gave reporters a detailed account of their various activities. These included farming, the construction of student dormitories, classrooms, a rehabilitation center, a clinic and a pig farm.Nkomo seemed to think the attacks had been carried out now to coincide with the visit of Smith and the three black Rhodesian leaders to the United States "How do they happen to be in Washington today and these incidents are happening?" he asked. "Is it coincidental or is it planned?"

The "arrogance" of Smith and Bishop Muzorewa in statements made after the attack "suggest this was well planned," he said.

Referring to Muzorewa as the "murderous bishop," Nkomo added, "This act of banditry will not go unpunished."