Gemfields Group Ltd. strengthened security at its shuttered Mozambican ruby mine, after the government released illegal miners from jail as part of its response to the coronavirus crisis.

Security guards have been equipped with firearms and patrol dogs have been deployed at the Montepuez mine, Gemfields said on Wednesday. About 150 illegal miners were released from prison in a nearby town to combat overcrowding.

Gemfields, the owner of colored gemstone mines and maker of Faberge jewelry, suspended operations at Montepuez today. At the beginning of February, more than 800 people invaded the mine, leading to almost a dozen people dying at one of the pits.

Montepuez, the world’s richest known ruby deposit, is located in the impoverished northern Cabo Delgado province. The region is at the epicenter of Mozambique’s Covid-19 outbreak, with Total SA’s $23 billion natural-gas project put under quarantine. The pandemic is another setback for the province, following an increase in attacks by insurgents linked to Islamic State.

This article was provided by Bloomberg News.