The leader of one of three rebel factions that sought to topple Congolese President Laurent Kabila said today that he would resume fighting following two government attacks on his troops last week.

"The Lusaka cease-fire no longer applies," Jean-Pierre Bemba, leader of the Congolese Liberation Movement, told Reuters, referring to the accords signed in August in the Zambian capital. "It is null and void. The cease-fire has now ended because of the repeated violations by Kabila."

The rebels' chief supporter, Uganda, said it still considers the agreement to be valid. Leaders of the other two rebel factions said that while they had interpreted statements made last week by Kabila's foreign minister as "a declaration of war," they would continue to abide by the agreement.

Bemba's pronouncement follows perhaps the most tense week in Congo since the 15-month civil war ended in August, and jeopardizes the fragile peace plan negotiated by the military government, three rebel factions and the five nations drawn into a battle that has destabilized central and southern Africa.

It also jeopardizes the U.N. peacekeeping mission in Congo, security experts and diplomatic officials said.

According to Bemba, 300 government soldiers attacked his group's territories in northwest Congo Friday but were beaten back. That assault, he said, followed two air bombardments earlier in the week of rebel-held territories, and another government effort two weeks ago that recaptured the town of Libanda.

Neither Kabila nor other officials have responded to Bemba's accusations, but the government and the rebels have repeatedly accused each other of cease-fire violations since the treaty was signed. On Saturday, government officials said rebels had massacred nearly 100 civilians in the eastern town of Kahungwe.

Foreign Minister Abdoulaye Yerodia said at a news conference last Monday that the government had rearmed its military forces and was "prepared" to carry out its "mission to liberate the country."

"We will not begin the next century under rebel occupation," he added.

Rebel leaders and newspapers in the capital, Kinshasa, characterized Yerodia's comments as a battle cry, signaling the government's intention to resume fighting. And security experts in the region said the foreign minister's comments punctuated a month-long propaganda campaign intended to prepare the Congolese people for a resumption of fighting. Billboards have appeared in Kinshasa in recent weeks with the ominous slogan: "Peace has to be earned."

Zimbabwe, Angola and Namibia have sent troops to Congo in support of Kabila, while Uganda and Rwanda have recruited and financed the rebels who sought to overthrow his government. Rwanda and Uganda supported Kabila when he led the militia that toppled the autocratic government of Mobutu Sese Seko.

But the Rwandan and Ugandan governments--both headed largely by Tutsis, the tribe targeted by rival Hutu clansmen in the 1994 massacre in Rwanda--grew increasingly disillusioned by Kabila's close ties with the Hutu militiamen involved in the genocide.

Uganda's regional affairs minister, Amama Mbabazi, said today that the government had not withdrawn its support of the cease-fire, as did Bemba's counterparts in the Rwanda-backed Congolese Rally for Democracy.

"We plan to continue to hold our fire," said Ernest Wamba dia Wamba, head of the Congolese Rally faction based in the northeastern Congo town of Kisangani. "In our opinion, we must give peace a chance in order for it to work." He said today that his group had not yet verified Bemba's claims of government attacks on his troops last week.