Siblings of Singapore Prime Minister Lee Hsien Loong have issued an unprecedented public statement attacking the country’s leader and accusing him of misuse of power in what could be a seismic fracture in the legacy of their late father Lee Kuan Yew.

The statement by Lee Wei Ling and Lee Hsien Yang — titled What Happened to Lee Kuan Yew’s Values — expresses a lack of confidence in their brother and the prime minister to lead Singapore, alleging he is “milking” the legacy of their father to retain power.

“Since the passing of Lee Kuan Yew, on 23 March 2015, we have felt threatened by Hsien Loong’s misuse of his position and influence over the Singapore government to drive his personal agenda,” the statement says.

“We are concerned that the system has few checks and balances to prevent the abuse of government.”