Ethiopian Prime Minister Abiy Ahmed said Friday that the killing of a popular singer, and subsequent violence that has left nearly 100 dead this week, represented "coordinated attempts" to destabilize the country. Speaking during a meeting with high-ranking officials, Abiy did not identify who he blamed for the unrest, though he vowed to hold to account those directly involved as well as "those that are pulling the strings", according to a summary of his comments distributed by his office. Abiy, last years Nobel Peace Prize laureate, wore a military uniform during the meeting, a portion of which was broadcast on state television. Singer Hachalu Hundessa, a member of the Oromo ethnic group, Ethiopias largest, was shot dead in the capital Addis Ababa on Monday night. Protests immediately broke out in the city and the surrounding Oromia region. Officials said Thursday night that 97 people had been killed by security forces and in inter-ethnic clashes. Five people have been arrested in connection with Hachalus killing. Officials have repeatedly suggested that the Oromo Liberation Army, a rebel group, and the Tigray Peoples Liberation Front, an opposition party, were implicated. Abiy, who won the Nobel in part for opening up Ethiopias political space, on Friday said opposition groups that benefited from amnesties he granted when he came to power in 2018 were taking up arms "instead of making a winning case through ideas and policy options", the summary provided by his office said. "A losing mindset cannot give birth to new ideas," it quoted Abiy as saying. Three high-profile opposition leaders -- including former media mogul Jawar Mohammed -- have been arrested in connection with the unrest this week, though officials have provided few details about the cases against them. Many businesses and government offices reopened in Addis Ababa on Friday after being closed for several days, but the internet remained shut off throughout the country for a fourth day.