The EU's chief observer at last year's elections in Ethiopia, Ana Gomes, has said a leaked report confirms serious government human rights violations.
The report says that 193 people were killed in two waves of protests
The report, leaked by Ethiopian judge Wolde-Michael Meshesha, claimed police massacred 193 protesters in clashes after disputed elections.
Ms Gomes accused western leaders of turning a blind eye, and preferring not to take action against Ethiopia.
The report's contents are hearsay, a government spokesman told the BBC.
"This only confirms what we have said in our report on the elections," Ms Gomes told the BBC.
"We pointed out that indeed there were massive human rights violations," she said.
"European leaders have been turning a blind eye because they want to turn a blind eye.
"They just pretend this is not true because they want to continue dealing as usual with the Ethiopian regime," she said.
Meanwhile, Ethiopia's ambassador to Britain, Berhanu Kebede, dismissed allegations that the government tried to suppress the independent report.
"This is a report that has been commissioned by the parliament and the report will be submitted directly to parliament," he said.
The report said the government used "excessive force" to crack down on protesters who claimed the elections had been rigged.
Ethiopian security forces said 58 people, including seven police, had died during an attempted revolution.
People took to the streets of the capital, Addis Ababa, and other cities in June and November last year to protest at the official results of May's general elections.
Students accused the police of brutality
The report said that the government had concealed the true extent of deaths at the hands of the police.
It said that 193 people had been killed, including 40 teenagers. Six policemen were also killed and some 763 people injured.
They had been shot, beaten and strangled.
The judge described the deaths as a massacre and said the toll could well have been higher.
"The police fired, definitely, as a kind of massacre of the demonstrators - especially in Addis, where more than 160 civilians were dead," by shooting, he told the BBC.
He said there was no doubt that excessive force had been used.
He claimed he had been put under pressure to alter his findings and fled into hiding in Europe when he received anonymous death threats.
More than 100 opposition leaders, journalists and aid workers were rounded up during the protests and are currently on trial, accused of treason and attempted genocide.