Some 4,500 residents of Sumatra Island in Indonesia joined 3,900 of their compatriots Friday in a lawsuit over the disruption to their lives caused by a hydroelectric project funded with Japanese foreign aid.

The suit was initially filed in September with the Tokyo District Court.

The plaintiffs are seeking 42 billion yen in compensation, or 5 million yen each, from Japan, arguing that some 20,000 residents were forcibly resettled to areas without proper living amenities or job opportunities when the hydroelectric dam, funded with official development assistance, was completed in 1996.