Ethiopian security forces fatally shot several dozen people in weekend protests across the country as frustration with the government grows, an opposition leader and Amnesty International said Monday, while hundreds staged a rare demonstration in the capital after calls via social media.

The government again blocked the Internet over the weekend, alleging that “anti-peace elements” based abroad and online activists were to blame for the violence.

In a statement, Amnesty International said that at least 67 people were killed in the Oromia region alone when security forces fired on protesters and that at least 30 were fatally shot in the northern city of Bahir Dar. The rights group cited “credible sources” and said hundreds of people were detained.

An opposition politician, Mulatu Gemechu of the Oromo Federalist Congress party, said that more than 70 people were killed across Oromia. “Many others were injured, and we have lost count of the number of those who were arrested,” he said.

The protests in several parts of the country highlighted growing tensions between Ethiopia’s citizens and its leaders. In a rarity, people carriedbanners criticizing political heavyweights and displayed the East African country’s former flag, used by the military government that the current administration overthrew in 1991.

“We need freedom,” one banner said. Demonstrations occurred despite the government’s warning against unauthorized gatherings.

Ethiopia, a close security ally of the West, is often accused by rights groups of stifling dissent. The U.S. Embassy said in a statement that it was “deeply concerned with the extensive violence.”

However, Ethio­pian Deputy Prime Minister Demeke Mekonnen told Fana Broadcasting Corporate on Monday, “We will not tolerate bodies that aim to overthrow the government and the constitutional order of the country by force.”

The protesters rallied around various causes. In Bahir Dar, the northern Amhara region’s capital, they demanded the reinstatement of the Wolqayit area in the Tigray region to the Amhara administration.

The arrest of members of a committee set up to oversee the reinstatement led to violent clashes over the past week.

The arrests also ignited weekend demonstrations in the Oromia region. Protesters demanded the release of people detained earlier this year in massive demonstrations against plans by the capital, Addis Ababa, to expand its territory into adjacent Oromia lands. The proposal has since been retracted.