Some divers rescuing the boys trapped in a cave in northern Thailand have traversed about 10 miles (16 km) over the past two days.

The second shift of the rescue effort to evacuate the trapped soccer team saw a team of 18 Thai and international divers guide four boys about 2 1/2 miles (4 kilometres) to the cave's entrance using a 3-mile (4.8 kilometre) rope on Monday.

It was the second trip down the dark and narrow passageways for some of the rescue team members, according to The Guardian.

"The factors are as good as yesterday, and the rescue team is the same team with a few replacements for those exhausted," Narongsak Osatanakorn, the governor of Chiang Rai province who's leading the operation, said Monday, The Guardian reported.

For the first four rescues on Sunday, two divers accompanied each boy, one from the side and one from behind.

In total, 13 foreign cave divers and five Thai navy SEALs participated in Sunday's rescue, according to Reuters.

Dozens of other medical professionals and rescuers were at the cave entrance to assist the divers when they emerged with the boys. On Monday, at least 80 other rescue workers from several countries were there to help.

The rescue effort, headed by the Royal Thai Navy's SEAL unit, have evacuated eight of the 12 boys, 11- to 16-year-old members of a Thai soccer team. Four boys and their 25-year-old coach remain in the cave.

The rescue workers need 20 hours before the third operation, Osatanakorn said Monday afternoon, according to a Guardian reporter. But weather and water levels will also affect plans for the final rescue.

About 0.6 miles (960 metres) of the journey on Sunday was believed to be underwater, requiring the boys to wear full face masks, Business Insider's Alexandra Ma reported.

Headcam footage posted by The Guardian shows the divers' journey through the dark, wet passages, where a diver died early Friday while delivering oxygen tanks to the cave.

Ben Reymenants, one of the divers who first found the boys a week ago, described to The New York Times the strength of the current inside the cave.

"You're literally pulling yourself, hand over hand, in zero visibility," he said. "You can't read your depth gauge, you can't read the time, so you're basically flying blind in a direction you don't know."

The boys and their coach have been trapped inside the Tham Luang cave for over two weeks because of monsoon flooding.

This article was originally published by Business Insider.

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