(CNN) -- Authorities listed the nationalities Saturday of the 29 miners trapped in a New Zealand coal mine and said gas levels inside are still too high to attempt a rescue.
Most of the miners are New Zealanders, but there are also two Australians, two Britons, and one South African, New Zealand Police said.
Air samples taken late Saturday afternoon indicated the gas levels inside the Pike River mine were still high, making the risk for rescuers too great, said Gary Knowles, superintendent of the Tasman Police District, who is heading the rescue effort.
"Further samples will be taken in the morning, when the risks will be reassessed," he said. "It is a very complex situation and there are numerous risks we have to consider. We will continue to work through the night, and constantly reassess the situation".
An explosion rocked the mine, on New Zealand's west coast between Greymouth and Reefton, around 4 p.m. Friday (10 p.m. ET Thursday). Two men walked out with minor injuries, but their colleagues -- ages 17 to 62 -- were trapped as far as 2.2 kilometers (1.4 miles) from the tunnel's opening and have not been heard from since.
"Everyone here is totally focused on getting these men out and returning them to their families," Knowles said.
CNN
