World Health Organization (WHO) experts will come to central-south China´s Hunan province to work with their Chinese peers to probe three possible human cases of bird flu in China, a spokesman said Thursday.

"We will send a team of experts to Hunan province sometime next week," Roy Wadia, WHO spokesman in Beijing, told Xinhua over the phone.

The WHO experts will work with Chinese colleagues to take more samples from the patients and will see what the Chinese government wants WHO to do to help, Wadia said.

According to the Hunan Provincial Health Bureau, the WHO experts will conduct an retrospective investigation of the occurrence and treatment of the three pneumonia cases with unknown causes.

Experts from the provincial center for disease prevention and control said the lab tests may take two to three weeks to reach a final result.

No human cases have been reported in China.

On Oct. 17, a 12-year-old girl in Xiangtan county in Hunan Province died of pneumonia. Her brother also became sick with symptoms of fever, but survived. A 36-year-old school teacher was also hospitalized for the same symptoms. All were diagnosed with pneumonia

Since the three patients all came from Xiangtan county, where H5N1 avian influenza was reported, the possibility of human infection of bird flu hasn´t been ruled out. The Ministry of Public Health has invited WHO experts to work with Chinses peers in the probe.

China has experienced bird flu outbreaks in Anhui, Hunan, and Liaoning provinces and Inner Mongolia Autonomous Region in recent weeks that have killed thousands of birds.

Last year, China reported 50 bird flu outbreaks but no human infections.