Two people have been killed in an underground explosion at a mine in the Australian state of New South Wales (NSW), the first such incident of its kind since 2015.

Emergency services were called to the Endeavor mine at Cobar, about 700km (435 miles) northwest of Sydney, in the early hours of Tuesday after reports two people had been critically injured.

Police said a man, in his 60s, was confirmed dead at the scene and two women, both in their 20s, were brought to the surface, but one later died. The second woman was airlifted to hospital for minor injuries and shock.

Polymetals Resources, which bought the Endeavor mine in 2023, said all operations at the site had been temporarily suspended.

It did not say what caused the explosion. The company's executive chairman Dave Sproule said it was shocked and saddened by the tragic incident and our deepest thoughts and condolences go out to the employee's families, friends and colleagues.

Fatalities from mine explosions are rare in Australia, with the most recent death happening in 2015 at a mine in Queensland according to Safe Work Australia.

Cobar Mayor Jarrod Marsden described the situation as absolutely tragic, emphasizing that families lost their loved ones.

A report will be prepared for the coroner and an investigation into the incident will be carried out by the state's workplace safety authority.

NSW Premier Chris Minns extended his condolences to the affected families, stating that this heartbreaking event would be felt across the entire mining industry.

Safety protocols and procedures have greatly improved in mining, but this tragedy is a sobering reminder to remain vigilant in protecting workers, he said.