(CNN) Singapore's first and only Olympic gold medalist Joseph Schooling has apologized for consuming cannabis while training and competing in Vietnam.
Schooling, a swimmer, confessed on Tuesday to having used the drug in May during a period when he was competing in the Southeast Asian Games, at which he won two golds and a bronze.
"I made a mistake and I'm responsible for what I've done. I demonstrated bad judgment and I am sorry," said Schooling, 27, in a personal statement seen by CNN.
"I am sorry that my actions have caused hurt to everyone around me, especially to my family and the young fans who look up to me," he added. "I won't let you down again."
It is unclear what prompted the confession from Schooling, who was competing while on leave from national service in the Singaporean military. Also unclear is the extent of any punishment he faces, though the Singapore government has said he will no longer be given leave from military service to train or compete.
Schooling's military service, which began in January, is expected to last until 2024, meaning he is unlikely to be able to compete in next year's World Aquatics Championships, Asian Games or Southeast Asian Games.
Further censure is possible, with the sport's governing bodies, Sport Singapore and the Singapore Swimming Association saying they will "review the facts of the case and determine appropriate steps to take."
The Southeast Asian Games did not immediately reply when asked whether Schooling's results in May would stand.
Singapore has laws against cannabis consumption that apply to its citizens even while overseas and allows for punishments of up to 10 years' imprisonment and fines of up to 20,000 Singapore dollars ($14,300). Vietnam also has strict laws on possession and use of drugs, with punishments ranging up to the death penalty.
Singapore's Defence Ministry said Tuesday that it had issued a formal letter of warning to Schooling and outlined the army's "strict zero-tolerance policy towards drug abuse."
"Those who are suspected of, or confessed to, abusing drugs will be placed on supervised urine test regimes as part of the treatment and rehabilitation process," the ministry said. "All (army) personnel who test positive during this regime will be charged and sentenced accordingly."
However, the Central Narcotics Bureau, the primary drug enforcement agency in Singapore, said on Tuesday that Schooling's urine tests for controlled drugs "returned negative".
In his statement Tuesday, Schooling called his actions a "moment of weakness" and said he had been going through "a very tough period in life."
His 73-year-old father, Colin Schooling, died last November after a battle with cancer and Schooling has previously spoken about the pressure of being in the public spotlight.
He first shot to fame in 2016 as a 22-year-old at the Rio Summer Olympics when he defeated his childhood hero, US swimming legend Michael Phelps, in the 100-meter butterfly to become his country's first Olympic champion. However, he faced intense criticism at home after failing to retain his title in Tokyo last year.