At least 11 people were killed and three injured when a gold mine collapsed in northern Burkina Faso over the weekend, the West African country's mining ministry said in a statement Monday.

"A collapse happened overnight from February 27 to 28 in a makeshift gold mine in Imyire village," the ministry said, adding that an inquiry had been launched into the cause of the accident.

One local elected official said the disaster was first reported "around 9 pm on Saturday", confirming the preliminary death toll of 11.

But "we don't know exactly how many people were inside" at the moment of collapse, he added, speaking on condition of anonymity.

The elected official added that eyewitnesses had seen the mine's beams fail, triggering a "domino effect" of collapse.

"Contraband explosives" were regularly used to extend the workings in unofficial mines, he added.

Deadly collapses are common in Burkina Faso's mines, especially in winter, and authorities struggle to manage independent gold mining.

The industry has in the past decade become a key economic sector for the poor country of 20 million people.

Gold production rose from 400 kilogrammes (900 pounds) in 2007 to more than 52 tonnes in 2018, according to Burkina's Mining Chamber, accounting for more than 10 percent of the country's economic output.

The formal mining sector generates over 60,000 jobs directly and indirectly, while makeshift mines and panning for gold employ as many as 1.5 million people and produce around 10 tonnes of gold annually, according to the mining ministry.

Gold is also exploited by jihadist groups for financing, according to the country's Economic and Social Observatory.

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