'Dozens' of workers trapped at Freeport's Indonesia mine

Rescue work is continuing at a major US-owned gold and copper mine in Indonesia after a tunnel collapsed on Tuesday, trapping more than 20 workers.

Police say four miners died and 10 others were evacuated after the tunnel caved in at Freeport's Grasberg mine, in the eastern province of Papua.

The situation at the mine is still thought to be volatile, police add.

Freeport has suspended all operations at the mine out of respect for the workers killed, the company says.

The head of Freeport's Indonesia unit, Rozik Soetjipto, says it is a temporary suspension out of sympathy for the victims but also due to some safety considerations around underground operations.

The accident has had no effect on the open mining pit at Grasberg, he adds.

Freeport, which is handling the rescue operation, said in a statement on Tuesday that "the rescue process is difficult and will take some time to complete".

About 40 workers were undergoing safety training at the time of the tunnel's collapse, said Freeport's Indonesia subsidiary.

The condition of the 10 people who were rescued is not known.

A police spokesman said the situation remained uncertain because the ground was shaky and rocks continued to fall.

The Grasberg mine has an estimated 24,000 employees.

In 2011, workers staged a three-month protest asking for better pay, with miners only going back to work after negotiating a pay rise of almost 40%.

The details surrounding the incident are difficult to verify independently, as foreign journalists are banned from reporting in Papua.

Indonesia says this is because the province is too dangerous for foreign media, but human rights groups say this is Jakarta's way of keeping observers out of the troubled province, says the BBC's Karishma Vaswani in Jakarta.

Papua became part of Indonesia in 1969 after a controversial election many Papuans say was a sham. A low-level war for independence has been waged in the province ever since.