Scores of people were killed across Ethiopia's Oromia and Amhara regions at the weekend as the security forces brutally suppressed a new wave of anti-government protests in two key regions.

An opposition leader told the AFP news agency that up to 50 people were killed, while Amnesty International said that more than 90 were killed.

The state-owned Ethiopian News Agency said "illegal protests" staged by "anti-peace forces" had been brought under control, but it did not mention casualties.

Police fired tear gas and blocked roads to several towns in the vast Oromia region as demonstrations erupted after a call from a spontaneous social media movement.

"We have reports of between 48 to 50 protesters killed in Oromia. This death toll might be higher because there were a lot of wounded," Merera Gudina, leader of the opposition Oromo People's Congress, told AFP.

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A diplomat confirmed that 49 people were killed. Among the towns worst hit by the violence were Nekemte, a town in western Ethiopia where 15 people were killed, the diplomat said, while 27 died in Bahir Dar, the capital of the Amhara region.

"They appear to be low level, quite disorganised protests scattered all around," the diplomat told AFP. "The brutal response of the government risks provoking more anger and making it worse."

Amnesty International put the death toll at 97, with 67 killed in Oromia and 30 in Amhara on Saturday and Sunday. The rights group said that the bloodshed in Bahir Dar may amount to "extrajudicial killings".

"Ethiopian forces have systematically used excessive force in their mistaken attempts to silence dissenting voices," Michelle Kagari, Amnesty International's deputy regional director for East Africa, the Horn and the Great Lakes, said.

Ethiopian authorities also imposed a blanket internet blockade over the weekend.

'Lots of shooting'

Oromia saw unrest for several months until early this year, sparked by plans to allocate farmland in the region, which surrounds the capital Addis Ababa, for development.

Authorities scrapped the land scheme in January, but protests have flared again over the continued detention of opposition demonstrators.

Hassen Hussein, an Oromo rights activist, told Al Jazeera he expected the protests to continue.

"It appears that hell has broken loose in Oromia and Amhara," he said. "The air is filled with death and mourning for so many people whose lives have been cut short by the security forces."

At the weekend, protesters chanted anti-government slogans and waved dissident flags. Some demanded the release of jailed opposition politicians.

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In the Amhara region, at least two people were killed in the ancient city of Gondar in clashes over the status of a disputed territory.

Tensions have been rumbling for two decades over Wolkayt district - a stretch of land that protesters from Amhara say was illegally incorporated into the neighbouring Tigray region to the north.

The demonstrators accused the government of rights abuses and marginalisation of ethnic communities.

The Oromo are Ethiopia's largest ethnic group, making up more than 30 percent of the population of about 100 million. The Amhara are the second biggest group.

The opposition says that the government and the military are dominated by the Tigrayan ethnic group, who make up about 6 percent of the population.

In Addis Ababa "many people were beaten," said a witness who did not want to be identified.

"I saw others getting arrested. The government was out with guns in town. They're moving with so-called special forces. There was lots of shooting," he told the DPA news agency.