Photo taken on July 8, 2018 shows that the first two boys are transfered to the field hospital after being brought out near the cave in Chiang Rai, Thailand. Four boys of 13 trapped in a northern Thailand cave have been brought out through an underwater evacuation, a member of the rescue team said on condition of anonymity Sunday. (Xinhua/Rachen Sageamsak)

CHIANG RAI, Thailand, July 8 (Xinhua) -- Four boys out of a total of 12 young soccer team members and their coach have been rescued after being trapped in a cave in northern Thailand for more than two weeks, a Thai official in charge of the rescue operation told reporters Sunday.

The boys were rescued using full face masks, with the first one emerging out of the cave at about 17:40 local time Sunday, followed by the second one 10 minutes later, Chiang Rai governor Narongsak Osottanakorn told a press briefing at the site after the first successful operation.

The third boy emerged from the cave at about 19:40 local time, tightly followed by the fourth one. They have all been hospitalized, according to the governor.

Helicopters were roaring overhead and cheering erupted at the media center following the official's remarks.

The next operation for the rest is set to resume in 10-20 hours, with officials and volunteers buoyed by the fact that their method of rescuing the boys by diving has been successful so far, he said.

"We've used all the oxygen," Narongsak said, adding that the clock is continuing to tick for the remaining boys who are still waiting in the cave along with their coach, and rescuers are going to focus on refilling the oxygen tanks so they can continue the operation.

Those who joined the extraction Sunday will have a meeting to discuss the next operation.

"Today is D-day for the extraction, with the boys at their best mental and physical conditions and medical teams as well as rescue teams ready for operation," said the governor.

Thirteen foreign cave diving experts have entered the cave to join the rescue operation since 10:00 local time on Sunday. The boys were dived out from the cave one by one, escorted by two divers at one time.

International rescue teams from the U.S., China, Australia and Europe are stationed along tunnel walls from the entrance of the cave to chamber 3, a safe command center inside the cave, to support the extraction.

The 12 boys, aged between 11 and 16, and their coach, 25, went missing in Tham Luang Nang Non cave in northern Thailand's Chiang Rai Province on June 23. They were located on a small cliff about four km away from the cave entrance when the search entered the ninth day on July 2.