Indonesia's health ministry say local tests indicate two more siblings have died of bird flu in the country.

Health officials say the 18-year-old boy and 10-year-old girl died Tuesday at a hospital in West Java province.

Indonesia is already grappling with a separate bird flu case involving the largest family cluster ever reported.

World Health Organization scientists are investigating the bird flu deaths of seven members of a family from Sumatra island who may have infected each other. But, the scientists say there is no evidence of more widespread human-to-human transmission.

The scientists also have no plans to issue a pandemic alert.

The WHO has so far confirmed 33 cases of bird flu deaths in Indonesia.