YANGON, Myanmar (AFP) — A Myanmar ethnic minority armed group was battling junta troops in a ruby and gem-mining hub on Friday, the group and residents told Agence France-Presse (AFP), with reports of civilian casualties in shelling and air strikes.

The Ta’ang National Liberation Army (TNLA) launched attacks on junta troops earlier this week in Mandalay region and neighboring Shan state, shattering a ceasefire brokered by China in January.

Its fighters were inside Mogok, a town surrounded by hills rich with rubies, sapphires, spinel, aquamarine and other semi-precious stones, General Tar Bhone Kyaw told AFP, without giving details. 

AFP was unable to reach a junta spokesperson for comment.

Mogok residents told AFP the town had been hit by artillery shelling and air strikes by military planes since fighting in the area started on Tuesday. “As far as I know, four people including two women were killed yesterday because of artillery shelling,” one 57-year-old Mogok resident, who did not want to give his name, told AFP.

He said he and his family were sheltering elsewhere after the roof of their home had been damaged in an air strike. 

“We have no experience like this. It’s the first ever serious fighting in Mogok town.”

Myanmar produces much of the world’s rubies, and top quality stones from Mogok — known as “pigeon’s blood” for their deep red color — can fetch more per carat than diamonds.

The industry is notoriously opaque, with high-value rubies often smuggled over the border into Thailand or China to be sold directly to private buyers or made into jewellery.

For decades Myanmar’s junta and its opponents have taxed local miners for income.