Two more people have died from the H5N1 strain of bird flu in Indonesia, raising the number of deaths there to seven, the health ministry said.
Most Indonesian households keep live chickens for food
Tests were carried out on a woman and a teenage girl, both from Jakarta, who died earlier this month after coming into contact with dead chickens.
The H5N1 virus has killed more than 60 people in South East Asia since the latest outbreak began in 2003.
On Tuesday, China confirmed its first human death from the H5N1 virus.
"We received the test results this morning and both victims were positive for bird flu," health ministry official Hariadi Wibisono told news agency Reuters.
The first case of human infection in Indonesia was announced in July.
Most Indonesian households keep chickens for food or caged birds for pets.
The government is stockpiling doses of the anti-viral drug Tamiflu amid fears of an epidemic.
The Chinese health ministry announced the country's first human cases of bird flu on Wednesday. It said a 24-year-old woman, a poultry worker in the eastern province of Anhui, had died.
The H5N1 strain was also confirmed in a nine-year old boy in Hunan province, who survived and is now recovering. It is suspected to have killed his 12-year-old sister, but since she was cremated before tests were carried out, there is unlikely to be an official confirmation.
The first human cases were widely reported by China's media on Thursday, allaying Western fears that the government was reluctant to acknowledge the problem. A WHO official called the Chinese response "very encouraging".
Also on Thursday, China reported two new outbreaks of H5N1 flu among poulty, in central Hubei and north-western Xinjiang.
The outbreak of the H5N1 strain among birds was first spotted in Vietnam and Thailand in 2003.
It spread to several other countries in the region and beyond, with reports of the disease among poultry in Russia and Kazakhstan in July 2005 - and outbreaks in Turkey and Romania.
The disease does not transmit easily to humans, and almost all the victims have had very close contact with infected poultry.
But experts warn that with every case of human infection, there is a risk of the disease mutating or combining with human flu and becoming more easily transmissible between humans, sparking the threat of a human pandemic.