The Tutsi refugees from Congo who survived the slaughter by Hutu extremists prepared to bury relatives and friends shot, hacked and burned to death in ethnic violence reminiscent of the 1994 genocide in neighboring Rwanda.
Burundian troops sealed the border with Congo on Sunday, with some manning the two official crossings and others monitoring the Ruzizi River that separates the two countries, army spokesman Col. Adolphe Manirakiza said Monday.
"It is one of the measures which we have taken to allow us to investigate the killings in Gatumba," Manirakiza told The Associated Press.
A Burundian Hutu rebel group based near the border claimed responsibility for the attack on the refugee camp in Gatumba. Officials said Hutu extremists from Congo and Rwanda were also suspected of taking part in the raid.
A spokesman for the group, the National Liberation Forces, claimed Burundian soldiers and Congolese Tutsi militia had been hiding in the refugee camp. But most of those killed appeared to be women and children.
The United Nations Security Council strongly condemned the massacre Sunday night "with the utmost firmness" and demanded that those who carried it out be brought to justice "without delay."
Burundian President Domitien Ndayizeye and Congo's Vice President Azarias Ruberwa prepared to attend a burial of the dead in a mass grave, while troops were moved to the border region to head off further violence targeting the Congolese Tutsi refugees, Manirakiza said.
The stench of burnt flesh and chemical preservatives applied to dead bodies hung in the air as relatives struggled to identify the victims, some of whom were charred beyond recognition.
Relatives wailed in anguish and others fainted in shock as the dead were placed in body bags and later sealed in coffins that were laid out in rows for burial in a mass grave about 2 miles from the camp.
The burial, which was originally planned for Sunday, was delayed until Monday to allow Congolese government officials to attend.
In Geneva, the U.N. High Commissioner for Refugees, Ruud Lubbers, called on the Burundian government to provide a new camp for the refugees and to protect them in the meantime.
The massacre echoed the , when majority Hutus slaughtered at least 500,000 minority Tutsis and Hutu moderates, and raised fears of retaliatory violence that could undo peace efforts in Congo after a 1998-2003 civil war that claimed more than 3 million lives.
It was the presence of Hutu fighters in eastern Congo that triggered Rwanda's involvement in the Congo civil war.
Complaints that the Tutsi minority was being threatened in eastern Congo triggered a .
Violence between Hutus and Tutsis has also characterized a civil war that has wracked Burundi for more than 10 years.
U.N. officials said at least 150 people were killed and 108 wounded in Friday's attack, but survivors said at least 161 were confirmed dead after seven bodies were recovered Sunday near the border with Congo.
"Many of the victims were very badly injured and most of them suffered wounds from bullets and grenade explosions," said Isabelle Abric, spokeswoman for the U.N. mission in Burundi.
Alexis Kamana, head of the Congolese Tutsi refugees, said more than 30 people were still missing.
Witnesses said the nighttime assault on the refugee camp was launched from across the border in Congo, about 1 mile away.
One group of assailants opened fire on a nearby Burundian army post to pin down troops while a second group raided the refugee camp, they said.