An armed group killed at least three refugees from the town of Tawarga on Monday near the Libyan capital as they tried to enter the city to hold a sit-in protest, a witness and other sources said.

The witness told AFP that a crowd of Tawargans, mostly black-skinned Libyans now living in refugee camps, came under attack near a camp outside Tripoli where the Tawargans have been staying for several months.

A government source confirmed the death toll but said the "deaths were due to a family quarrel among the Tawargans and not the result of a clash between two different groups."

The Tawargans stand accused by fighters from Misrata, the third largest city in Libya, of having taken part in the siege of their city and rape of their women during the bloodiest months of last year's anti-Kadhafi uprising.

The displaced Tawargans are now staying in refugee camps across Libya, in and around cities such as Tripoli, Benghazi, Hun and Sabha.

They accuse the people of Misrata of stopping them from returning to their homes in Tawarga, a town near the port city. They fled when Misrata fighters broke the siege of their city last year.

The witness said the Tawargans were headed to Tripoli's Martyrs Square to hold a demonstration when they were attacked.