The Thai youth soccer team trapped for 18 days in a cave were given drugs to control their nerves during the perilous three-day rescue operation, officials said.

During a news conference before the final rescue of four boys was complete, Thai Prime Minister Prayuth Chan-ocha said the boys were given an anti-anxiety medication to help with their perilous removal from the cave.

Prayuth was asked by a reporter if the boys had been sedated, to which he said: "Who would chloroform them? If they're chloroformed, how could they come out? It's called anxiolytic, something to make them not excited, not stressed."

This undated photo from video released via the Thai NavySEAL Facebook Page on Wednesday, July 11, 2018, shows rescuers hold an evacuated boy inside the Tham Luang Nang Non cave in Mae Sai, Chiang Rai province, in northern Thailand. (Thai NavySEAL Facebook)

A British diver involved in the rescue operation told The Daily Mail the boys were given something a bit stronger -- a dose of ketamine, which is known for being a horse tranquilizer. Another diver involved in the operation also told the news outlet the boys were given a drug that knocked them out.

"The boys were sedated – they were unconscious," Spanish diver Fernando Raigal told The Mail.

THAI CAVE RESCUE ALMOST ENDED IN DISASTER, AFTER MAIN PUMP REPORTEDLY FAILED

But the Thailand Health Department’s deputy chief disputed reports the medication given to the boys put them to sleep, according to Khaosod English.

“They were conscious when they arrived at the hospital … I don’t have any details about when they were being transferred from the cave,” Thongchai Lertwilairattanapong said.

Prayut also disputed suggestions the boys were not awake during the rescue, saying: "All of the children were conscious during the operation."

The boys were described as generally being in normal condition in a Chiang Rai hospital Thursday, though their levels of recuperation varied because they were removed from the cave at different times during three days.

Their relatives are being allowed to visit with them while wearing hospital gowns and masks after earlier being kept away from the boys for fear one group might spread infections to the other, according to the Associated Press.

The four boys rescued Sunday have normal heart rates and no fever, and two of them with lung infections are improving, said Jedsada Chokdumrongsuk, permanent secretary of the Public Health Ministry.

Two of the four rescued Monday have mild fevers, the secretary said in a statement. Three of the five in the last group have fevers that are easing, and three have middle ear infections.

All members of the group are receiving antibiotics and a psychiatrist was attending to the boys, who are sleeping well and are not showing symptoms of stress.

THAI CAVE RESCUE TIMELINE: THE DANGEROUS RACE TO BRING TRAPPED SOCCER TEAM HOME

The 12 Wild Boars players and their coach had entered the cave to go exploring June 23 but monsoon rains filled the tight passageways, blocking their escape. They were found 10 days later, huddled on a small, dry shelf just above the water, and divers and other international rescuers plotted the complex mission to rescue the team before more rain came.

A former Thai navy SEAL volunteering to work on the rescue died on July 7 during a supply mission inside the cave.

The Associated Press contributed to this report.