NAIROBI, KENYA,OCT. 5 -- Fighting broke out in the capital of Rwanda today, as France and Belgium sent troops to block a rebel force that invaded six days ago from neighboring Uganda, radio reports and foreign officials said.

Diplomats from Kigali, capital of this impoverished country in central East Africa, said the small-arms and artillery fire had died down later in the day and that the newly arrived French and Belgian forces were helping the Rwandan military maintain control of the city.

President Juvenal Habyarimana said in a nationwide address that government forces were in "full control" of the situation. "The worst is over," he said, as shots could be heard in the capital.

No casualty figures were available. Diplomats interviewed by telephone said it appeared that no foreigners had been hurt. "It looks like the French, Belgians and Rwanda militias have things under control," a diplomat said. "However, the streets still are not safe."

Habyarimana had requested military assistance from France and from Belgium, Rwanda's former colonial ruler, to beat back the invasion. The action was launched Sunday by Fred Rwigyema, a Rwandan refugee who is a major general in the Ugandan army, with a force estimated at between several hundred and several thousand rebels, many of them deserters from the Ugandan army. Most of the rebels, including Rwigyema, are Rwandan refugees from the minority but once dominant Tutsi tribe.

In Paris, the Foreign Ministry said a detachment of 150 French soldiers was being sent to Rwanda today to join 150 Foreign Legionnaires dispatched earlier. An estimated 670 French citizens currently are in Rwanda.

In Bonn, the German government said some of the 400 German nationals in Rwanda would be evacuated on planes to be sent in by France, and others in truck and car convoys to neighboring Burundi or Zaire.

An estimated 250 Americans, including tourists, are in the country of 6.7 million people.

Belgium also has rushed paratroopers and military equipment to Rwanda to protect its 1,630 citizens there.

{Reuter reported that the Belgian force comprised 600 paratroops, and quoted a French journalist as saying Zairian troops also had been dispatched to Kigali.

{An Air France plane carrying 139 foreigners, 130 of them French citizens, flew out of Rwanda Friday.

{Nairobi airport sources said the Belgian government had sent a DC-10 to Kigali for an evacuation flight, but the aircraft left empty a few hours later because of difficulties assembling people at the airport under curfew restrictions.}

Burundi state radio in the capital, Bujumbura, said refugees from Rwanda, including Europeans, were arriving at the border. It called the situation in Rwanda "confused."

Fighting erupted early today near government buildings and two military installations after a group of rebels infiltrated the capital, according to sources. {Reuter reported heavy fighting near the presidential palace.}

On Wednesday, a diplomatic source said Rwanda's army had stopped the main rebel force at Gabiro, 40 miles northeast of Kigali, in a counterattack. An army officer in Uganda also reported heavy bombing by Rwandan forces.

The government urged people to stay indoors and banned unauthorized travel and gatherings of more than two people. A dusk-to-dawn curfew was in effect.