Battles Rage in Rwanda as Talks Stall : Africa: Rebels reject U.N. plan to reopen airport in Kigali and launch fierce offensive on government positions. Peacekeepers can do little but take cover.

Heavy fighting raged around the airport in Rwanda’s capital Saturday, keeping Kigali’s last link to the outside world closed and raising doubts about the United Nations’ ability to establish a cease-fire.

A U.N. official in Kigali reached by phone from Nairobi said it was unclear whether the intensified fighting was the start of the rebels’ long-promised offensive to capture the capital. The rebels have said they plan to take the city before the United Nations dispatches about 5,500 more peacekeeping troops to Rwanda.

About 450 U.N. troops, mostly Africans under the command of Canadian Brig. Gen. Romeo Dallaire, are in Kigali.

With both sides in the ethnic battle apparently unwilling to halt their fire, the U.N. role has been reduced to a passive one spent in foxholes around the severely damaged airport facility.

The U.N. official in Kigali, Abdul Kabia, said that if the attacks on the airport continue, the troops may redeploy.

U.N. officials have been trying to broker an agreement whereby both sides would withdraw all weapons at least 1 1/4 miles from the airport.

But Saturday, U.N. spokesman Maj. Jean-Guy Plante said the rebels rejected the plan. “The rebels said it is too late,” he said.

No U.N. relief flights have been able to land at Kigali for three days because of the fighting, leaving the city seriously short of food and medicine. The Red Cross suspended its relief convoy after one of its physicians was wounded in an ambush Thursday.

Throughout the day Saturday, rebel mortars and rockets struck government positions around the airport. Six U.N. vehicles were destroyed, but there were no reported U.N. casualties. Other shells slammed into the city’s center, and small-arms fire was heard in villages on the capital’s perimeter.

The Kanombe army camp just east of the airport is defended by three battalions of government troops, from the Hutu tribe. But the hills overlooking the camp in the airport are controlled by the mostly Tutsi rebels of the Rwandan Patriotic Front.

The rebels claim to control about half of the country and apparently have cut the roads leading to Kigali. The government troops, supplied primarily by Zaire, are said to be running low on fuel and ammunition.

The Ugandan-supplied rebels have appeared to be in a position to launch a major offensive on Kigali for about 10 days, diplomats in Nairobi said, but their inability to dislodge the Kanombe defenders has delayed any decisive battle in the 4-year-old civil war.

Since fighting intensified last month, at least 200,000 people have been killed; some estimates put the toll at up to 500,000. At least 2 million Rwandans have fled the carnage.

Despite numerous failed cease-fires, special U.N. envoy Iqbal Riza is scheduled to arrive in Kigali on Monday to discuss with both sides an expanded U.N. role and the deployment of 5,500 African troops, approved last week by the Security Council.

Civil war has simmered in Rwanda since 1990. The latest round of ferocious fighting and appalling massacre began April 6, when Rwanda’s president, Juvenal Habyarimana, died in a plane crash at Kigali upon returning from a negotiating session with the rebels in Tanzania. His plane apparently was hit by a rocket. The president of Burundi, Cyprian Ntayamira, also died in the crash.

The rebel forces are mostly Tutsis, the tall, lithe minority that held the short, stocky Hutu majority in a form of serfdom for 400 years until a revolution in 1959. Almost 90% of Rwanda’s people are Hutu.

Since independence from Belgium in 1962, the Hutus have run the government, and fighting between the two groups has flared periodically. Fifteen months ago, Tutsi rebels launched an offensive that brought them to within 16 miles of Kigali. France flew in 400 troops to protect its nationals and, in the process, may have saved Kigali from falling.

The Tutsi rebels and the Hutu government reached an accord in Arusha, Tanzania, last August to end the war and lay the foundation for a broad-based transitional government and multi-party democratic elections. The two sides were struggling toward that goal when Habyarimana, a Hutu, was killed.

Most of the victims of the recent killings have been Tutsi civilians, not military personnel. Thousands died as Hutu mobs attacked Tutsi villages with machetes and knives. Hundreds of thousands of Tutsis--and some Hutus sympathetic to Habyarimana’s attempts to establish ethnic parliaments--have flooded into makeshift refugee camps in neighboring Burundi, Tanzania and Uganda.