ADDIS ABABA - Youths enraged by the killing of a popular protest singer burned tires during demonstrations in Ethiopia's capital on Tuesday, in a display of anger from the prime minister's own Oromo ethnic community.

Addis Ababa city police commissioner Getu Argaw told state media late on Monday that Haacaaluu Hundeessaa, an Oromo musician known for his protest songs, had been shot dead at around 9:30 in the evening. Some suspects had been detained, he said, giving no further details.

On Tuesday morning the normally busy streets of Addis Ababa were eerily empty as protesters lit fires and chanted slogans.

The internet connection to Ethiopia, Africa's second most populous nation, appeared to be down, a common occurrence during political protests.

Prime Minister Abiy Ahmed expressed his condolences, promised an investigation and asked the public to remain calm, in a message posted on Twitter.

Haacaaluu, a former political prisoner, rose to prominence during prolonged anti-government protests which propelled Abiy into office in 2018.

Abiy's Oromo ethnic group sparked the protests, and his rise to power ended decades during which the multi-ethnic ruling coalition was dominated by ethnic Tigray leaders.

His rule has ushered in greater political and economic freedoms in what had long been one of the continent's most repressive states, and he won the 2019 Nobel Peace Prize for ending conflict with neighboring Eritrea.

But the rise in political activism has also led to an increase in unrest in a country made up of more than 80 ethnic groups. Abiy's rule has been frequently challenged by local powerbrokers demanding more access to land, power and resources.

His pan-Ethiopian politics have sparked a backlash from some elements of his own Oromo powerbase, spearheaded by a media magnate, Jawar Mohammed.