IKONGORO, Rwanda -- Tutsi rebels advanced toward ?lite French troops in southwestern Rwanda on Tuesday, as the shell-shocked capital of Kigali slowly adjusted to rebel rule. About 500 soldiers patrolled the woodlands around Gikongoro, which the French have marked off as a haven for the 400,000 refugees they estimate have fled to the area to escape ethnic massacres in Rwanda's civil war. Troops dug in mortars and howitzers as Gikongoro's mayor drove through the streets with a loudspeaker urging calm and telling panicked refugees the French would protect them. The Tutsi-led Rwandan Patriotic Front said it would not respect the zone, which cuts between its rebel forces and the last third of the Central African country controlled by the Hutu-dominated government.French President Fran?ois Mitterrand insisted the rebel front "is not our adversary" and said France was not trying to keep the rebels from defeating government forces as it did in 1990. "We say simply that there must be somewhere a place for people in danger to take cover. We extend a helpful hand. Our action stops there," Mitterrand said during a visit to South Africa. But he also said French soldiers would fight to defend themselves. Rebel leaders threatened to attack the French contingent, which moved in last week to protect refugees and will reach its full strength of 2,500 men this week. "If the French stand in our way then it is the French who will have chosen confrontation," the rebel front's secretary general, Theogene Rudasingwa, said in London. A column of an estimated 2,000 rebels was on the march 20 kilometers from the zone, which is 135 kilometers southwest of Kigali, French Captain Jacques-Albert Roussel said. A French government official said in Paris that some rebels were less than 10 kilometers from French positions around Gikongoro. The official, who spoke on condition of anonymity, said those rebels were not moving and there was no fighting. UN officials estimate that between 200,000 and 500,000 Rwandans have died in the latest round of the war, most of them Tutsi civilians slain in ethnic massacres. The fighting began after Rwanda's president, Juvenal Habyarimana, a member of the majority Hutu ethnic group who had signed a peace accord with the rebels, died April 6 in a suspicious plane crash. In the rebel-held capital, gunfire died down after the final rebel assault Monday. Civilians who had fled during the three-month siege were beginning to return, said a UN spokesman, Pierre Mehu, in Kigali. "The city is calm, no gunfire, quiet," he said. "There has been no sign of vindictive killings." Rebels also appeared to have taken Rwanda's second largest city, Butare, 128 kilometers southwest of the capital, French military commanders said. About 210 soldiers from Ghana were to arrive in Kigali on Tuesday to bolster the small, lightly armed UN force deployed in the city, Mehu said. Government soldiers who fled Kigali on Monday apparently headed west to Gisenyi, a town on the Zaire border where Hutu government leaders have taken refuge. France intervened on June 23 to try to stop the massacres until the United Nations could send a promised force of 5,500 peacekeepers. On Saturday, the French expanded the humanitarian mission by declaring the no-fight zone to protect refugees. The rebels said they would not allow France to defend the government as it did in 1990, the year the rebels began the civil war. "We feel the French have no business in Rwanda," said Rudasingwa, the rebel leader. Although French commanders vowed neutrality and said they would keep both rebel and government soldiers from the protected area, thousands of government soldiers were flooding in. The French have manned the zone with ?lite paratroopers and the Foreign Legion. Trained in commando tactics, they have led numerous interventions in Africa.