The ethnic Tutsi refugees from the neighbouring Democratic Republic of the Congo were killed at Mudende camp, about 120 km (75 miles) northwest of Kigali, when it was attacked on Wednesday night by Hutu militiamen armed with rifles, grenades and machetes, according to a senior army official.
A total of 271 people were killed in the attack and 227 were wounded, said Colonel Nyamwasa Kayumba.
Yesterday morning survivors were burying the dead - mostly women and children and most bearing horrific wounds - just yards from the tents in which they were slaughtered.
One survivor, whose son was hacked to death, said: "They came very quietly while we were sleeping and we had no chance to escape. They just started chopping, chopping, chopping."
The UN refugee chief, Sadako Ogata, strongly condemned the attack and a spokeswoman called the attackers merciless.
The US Secretary of State, Madeleine Albright, told a news conference in Congo that she was asking US war crimes envoy David Scheffer to go to Rwanda to assist in the investigation of the massacre.
Mr Scheffer, who has been accompanying Mrs Albright on a seven-nation African tour, had been asked to go back to Rwanda, to try to assist in the probe of the killings.
Mrs Albright, the most senior US official to visit Rwanda since a genocide in 1994, has condemned a recent upsurge of violence in the country connected with the return from Congo of hundreds of thousands of Hutu refugees who fled their country in 1994, fearing reprisals for the genocide. Some 800,000 Tutsis and moderate Hutus died in Rwanda in 1994 during a genocide by extremist Hutu militia and members of the former government and army. Rwanda's government fought its way to power during the genocide. Reuters, Mudende