- Prior to his arrest, the rapper had received several warnings from authorities for producing music critical of the junta, they added.
- The song has also re-emerged in the current civil war that has been raging since the coup in February 2021.
One of Myanmar's biggest hip-hop artists has been detained for criticising the military government on Facebook, the BBC has confirmed.
Byu Har criticised the junta's handling of nationwide power outages that have hit Myanmar in the past months.
The country has struggled to secure supplies for gas-fired electricity plants since the 2021 coup which ousted Aung San Suu Kyi's civilian government.
His detention is just the latest in the regime's crackdown on critics.
Byu Har, who had been based in Yangon, had called the electricity minister "a fool" and "incompetent" in a video posted to Facebook on Tuesday night.
"During the past five years under the old lady, we had 24 hours of electricity, not only that, the electricity bill was [going] down," he said referring the former democratically-elected leader Ms Suu Kyi.
The rapper used incendiary language to refer to the junta's leaders and also included his home address in the video's caption, inviting them to arrest him if they took issue with the post.
The musician was detained in Yangon's North Dagon Township by police on Wednesday before friends and family lost contact with him, sources familiar with the incident told the BBC.
Prior to his arrest, the rapper had received several warnings from authorities for producing music critical of the junta, they added.
It is unclear where Byu Har is being held or what condition he is in.
Myanmar's authorities routinely subject detainees to extreme interrogation and torture, the details of which have been documented by human rights organisations such as Amnesty International.
Byu Har is the son of Naing Myanmar, one of the Southeast Asian nation's most prominent musicians.
Naing Myanmar's song "The World Will Not End", became an anthem during the 1988 revolution, which saw student activists lead a nationwide uprising against the former military regime.
The song has also re-emerged in the current civil war that has been raging since the coup in February 2021.
Two years on, the military government has failed to gain authority over large areas of the country. It is battling established ethnic armed groups in border areas that have been at war with the military for decades, and recently-formed anti-coup militias that call themselves People's Defence Forces (PDFs) in much of the rest of the country.
Many thousands of people have been killed and some 1.4 million have been displaced since the coup. Nearly one third of the country's population is in need of aid, according to the United Nations.