A blast in northern Myanmar killed dozens of people on Sunday, two rescue workers said, with rebels controlling the region saying it was caused by the accidental detonation of mining explosives.

One first responder in Shan state's Namhkam district, where the blast occurred, said 46 people were killed, including six children, and more than 70 others were injured.

The massive explosion destroyed many houses and injured people were transported to a local hospital, said the emergency worker, who spoke on condition of anonymity due to security concerns.

"There could be more dead people under their destroyed houses," he added.

Another rescuer, who also asked not to be named, said the death toll was higher, at 59 killed, and bodies were collected by emergency personnel for cremation.

Myanmar has been mired in a civil war since the military grabbed power in a 2021 coup, with the armed forces fighting an array of pro-democracy guerrillas and powerful ethnic minority armed groups.

The Ta'ang National Liberation Army (TNLA), one of the country's most powerful ethnic minority factions, said the "accidental explosion" of stored explosives used in mining and stone quarrying detonated at around 12:00 pm (0500 GMT) on Sunday in Namhkam.

"Because of this explosion, many local villagers lost their lives and suffered injuries and damage to their homes," the TNLA said in a statement, without giving a specific toll.

The explosives belonged to its economic department, and the exact cause of the blast was under investigation, the group said.

Many rebel groups in Myanmar rely on mining of precious minerals to fund their campaigns against the military, with lax safety measures making mine collapses and other accidents common.

The country's borderlands are home to a myriad of ethnic minority armed groups, many of which have battled the military since independence from Britain in 1948 over autonomy and control of lucrative resources.

The so-called "Three Brotherhood Alliance" of ethnic minority armed groups -- made up of the TNLA, the Arakan Army (AA) and the MyanmarNational Democratic Alliance Army (MNDAA) -- agreed to a China-brokered ceasefire with the military in early 2024.

But in June that year, the TNLA launched fresh attacks in Shan state and the neighbouring Mandalay region.

That summer the rebels captured the northern ruby-mining town of Mogok, with the TNLA driving the opposition offensive.

Then in October last year, the TNLA said it had agreed to a withdrawal from Mogok, which was mediated by China.

Beijing is a key power broker in Myanmar's civil war, analysts say, supporting both rebels and the military on a sliding scale according to its economic and security interests.