GENEVA - The knowledge on the deadly strain of avian influenza H7N9 which caused two deaths in China as of now is limited and further investigation will be needed, a spokesperson of the World Health Organization (WHO) said Tuesday.

Fadela Chaib confirmed that it's the first time that H7N9 was found in human beings.

"It has shown, for the time being, no human-to-human transmission," she said.

She told reporters that it's an important event and of concern to WHO. China will share information with WHO and WHO will share information with member states.

"We need to further investigate the extent of the outbreak, the source of the infection and the mode of transmission," she said.