The Human rights watch said police had shot 30 people dead in the city.
It said on Monday, August 8, in Addis Ababa that government had earlier said only seven people had been killed, all of them in Bahir Dar, the capital of the north-western region of Amhara, as protesters clashed with police.
Amnesty, however, said that police had shot 30 people dead in the city.
It said that in addition, 67 people were killed in clashes in Oromia, Ethiopia's largest region covering part of the south and west.
The rights group said that the demonstrators in Amhara and Oromia accused the government of rights abuses and marginalisation of ethnic communities.
It said that government has again blocked the internet for the second time in two months, allegedly to curb calls for protests.
The Human Rights Watch said that Oromia had previously seen months of protests against plans to extend the boundary of Addis Ababa amid concern that it could lead to farmers being displaced.
The protests had led to security forces killing more than 400 people then, according the Amnesty International.
It said further that the boundary plan was abandoned, but resentment still festers among the Oromo community, which feels excluded from political and economic power.
The watch noted that in Amhara, the protests focused on federal boundaries drawn two decades ago that, according to local critics, cut off many ethnic Amharas from the region.
Amnesty expressed concern that the hundreds of people who had been arrested could be tortured.
The Oromo are Ethiopia's largest ethnic group, constituting more than 30 per cent of the population of 100 million, while the Amhara are the second-largest group.
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