Four foreign tourists have died of suspected methanol poisoning in Laos, officials said on Thursday.
Among the dead were an Australian woman, two Danish citizens and a US citizen.
What do we know about the suspected methanol poisoning case?
A group of around a dozen tourists fell ill after a night out on November 12 in the town of Vang Vieng, some 130 kilometers (81 miles) north of the capital, Vientiane.
Vang Vieng is a popular destination for backpackers traveling through Southeast Asia.
An Australian tourist had been taken to hospital in Thailand in the incident and was confirmed dead by Australia's head of government on Thursday.
"Tragically, Biana Jones has lost her life. Our first thoughts at this moment are with her family and friends who are grieving a terrible and cruel loss," Australian Prime Minister Anthony Albanese said in Parliament.
A second Australian tourist was in critical condition, Albanese added. Her father told Australia's Channel Nine broadcaster that she was on "life support" in a hospital in the Thai capital of Bangkok.
Laos police told the AFP news agency they detained the Vietnamese manager of the Nana Backpackers Hostel in Vang Vieng, where the two Australian tourists had been staying.
Also on Thursday, Denmark's Foreign Ministry reported the deaths of two Danish citizens in Laos. The US State Department also confirmed that one US citizen had died. Neither agency gave further details.
Meanwhile, New Zealand's embassy in Thailand said it had been contacted by one of its citizens who had fallen ill and may be a victim of the mass methanol poisoning in Laos.
What is methanol?
Methanol is often added to bootleg alcohol to increase its potency, but it can also impair vision, digestion and brain function and in some cases cause death.
Hundreds of people die each year from the consumption of tainted liquor.
In June, at least 34 people died and dozens more were hospitalized in the southeastern Indian state of Tamil Nadu after they drank methanol-laced illicit alcohol.