U.N. aid workers persuaded tens of thousands of Rwandan refugees on Sunday to return to their camps inside Burundi, which they had fled in fear last week.

The government of Burundi also launched a nationwide campaign to calm ethnic tensions that killed at least 150 people in the capital, Bujumbura, a week ago.Encircled by soldiers with automatic weapons, President Sylvestre Ntibantunganya found his message of peace received with cheers, open hostility or indifference depending on the ethnic mix in each neighborhood he visited.

Even as the president spoke in one relatively calm area, Hutus and soldiers clashed nearby, leaving three men dead and one woman seriously injured.

The violence underscored the depth of the suspicion and hate that divide Burundi's majority Hutus and minority Tutsis, who have slaughtered each other by the hundreds of thousands over the last 30 years.

Similar ethnic tensions led to last year's massacre in neighboring Rwanda of about 500,000 people, mostly Tutsis, by soldiers of Rwanda's former Hutu-led government and Hutu militias.

The Rwandan refugees in Burundi are mainly Hutus who fled their homeland after Tutsi rebels defeated the former Hutu regime.

Up to 50,000 of them packed up their meager belongings again amid last week's attacks on Rwandan refugee camps in northern Burundi. They headed for Tanzania, only to be stopped Friday when Tanzania closed the border.

The refugees at first refused to turn back, but thousands huddled in a squalid camp near the village of Gashoho were persuaded to return by international aid workers.

"Clearly they've decided they would be better off to go back where they came from. Right now they are out in the middle of nowhere with nothing," said Paul Stromberg, a spokesman for the U.N. High Commissioner for Refugees.

He estimated that from 10,000 to 15,000 refugees would be returned on trucks on Sunday and Monday to camps at Ruvumu and Kibezi in northern Burundi. However, Stromberg said the Burundian military has barred the 41,000 Rwandans who fled the Magara camp from returning to that site.

Those refugees have been moved to a temporary site near Gashoho. Aid workers will provide water, emergency medical care and basic sanitation, but food will not be distributed so the refugees don't stay, he said.

In Bujumbura, Defense Minister Lt. Col. Firmin Sinzoyiheba said Cabinet officials will be crossing the country over the next month to try to prevent further violence.