A leader of the Ugandan group that attempted to overthrow Idi Amin last month says that the organization still has forces inside and outside Uganda and that it is determined to continue its efforts to restore representative democracy and prosperity to the country.

The Ugandan, a military officer, who insists that he not be identified, said that the Uganda Liberation Movement planned and carried out its attempted coup on June 18 without any outside help, but is now convinced that future efforts will require external aid.

He said the rebels have no intention, however, of joining forces with Ugandan exiles in Tanzania who are loyal to former President Milton Obote. Amin deposed Obote in a military coup in 1971.

"We want something entirely new." the officer said. "If Obote came back to power we are afraid he would first try to settle old scores, but we want the killings to stop and aren't interested in revenge.

"Our aim is to liberate Uganda from Amin and his stooges, his henchmen and the Anyanya group."

The Anyanyas are southern Sudanese soldiers who, in 1972, after 17 years of civil war, signed a truce with the Sudanese government. Since then many of them have been recruited into Ugandan military service.

According to the Ugandan officer, 95 per cent of Amin's dreaded security force, the State Research Bureau, are either Anyanyas or Nubians, another group with Sudanese origins.

The anti-Amin Liberation Movement claims that the Sudanese are now the privileged class of Uganda, their ranks swelled by imigration of ethnic Sudanese from Kenya and other countries.

The Liberation Movement officer says that Amin, who is of Sudanese Descent, is deliberately creating a Sudanese fiefdom in Uganda, with himself as feudal lord, the Anyanya and Nubians as his vassals and ordinary Ugandans as expendable serfs.

The Uganda Liberation Movement, the officer said, was founded last July by an air force major, a member of Amin's State Research Bureau and a civilian businessman. An air force captain and his brother, and army lieutenant, later assumed leading roles.

The group gradually expanded, the officer said, but security was so tight that most of the members never knew each other. From the beginning, the chief task was stealing weapons from the army.

This was accomplished mainly through hijackings, the officer said, because in Uganda's forces "people who can read and write and everyone Amin doesn't trust 100 per cent have no arms and don't even know who has the key."

A few civilians began joining the movement's military core last November, the officer said, but only 50 conspirators were actually party to the June 18 plot, although another 150, mostly soldeirs, were recruited a few hours before the coup attempt took place.

Rebel leaders, already looking forward to another attempt, believe that recruitment of Ugandans within the country and exiles from outside will not be a big problem but that financing the purchase of weapons will be.

"When we see the difficulties facing us now we despair, but we are determined not to give up the struggle," said the military officer. He believes that the June 18 plot failed because of a security leak and a false rumor that Amin h* ad been assassinated a few days earlier.

The week befor e D-Day, while Radio Uganda was reporting that Amin was on his way to the Commonwealth summit meeting in London, it was rumoured that he had been killed. Amin learned of the rumor and tightened his security, the officer said.

Then on D-Day morning, he said Amin learned there was a plan to kill him while he officiated at a ceremony at Enteabbe Lodge, 25 miles from Kampala.

As a result, Amin loyalists were able to intercept an advance group of rebels near Entebbe, killing some and dispersing the rest. This information did not reach the coup leader in Kampala, however, and so, the officer said, three other groups of plotter began the trip to Entebbe on schedule.

On the way, the officer said, they happened upon Amin and his strengthened group of bodyguards. Shooting followed. Details are not known here because none of the rebels escaped, but one Ugandan who claims to have witnessed the fighting says the driver and a passenger in Amin's car were killed by a bazooka shell.

The coup leader was still in Kampala directing soldiers who were preparing to take over the radio station, post office and telephone exchange, parliament buildings, the State Research Bureau headquarters. When he learned of the plot's failure he drove to Kenya, successfully getting past Amin's roadblocks.

Twelve of his colleagues also reported escaped that night. The air force captain, who is second in command, and the businessman who helped found the Liberation Movement also are safe but the State Research Bureau man was killed on the day of the attempted coup, the officer said.

The coup 's leaders say their immediate goals had been to wipe out resistance and arrest and try all who had committed crimes under Amin.