SINGAPORE (AP) — A tussle that began over their father's will escalated Wednesday when two siblings accused their brother, the prime minister of Singapore, of using "the organs of state" against them and grooming his son to take up a political role in the tightly-controlled city-state.

Business executive Lee Hsien Yang, the brother of Prime Minister Lee Hsien Loong, said the situation compelled him to leave Singapore "for the foreseeable future." He and his sister, a well-known neurosurgeon Dr. Lee Wei Ling, said in a statement "we feel big brother omnipresent."

The feud offers a rare glimpse into cracks in the prominent family after the death of Lee Kuan Yew, who led Singapore with an iron grip for more than three decades and is credited with transforming the resource poor island into a wealthy bustling financial hub with low crime and almost zero corruption.

Such grave accusations directed at a leading official are extremely rare in Singapore. Since taking power in 2004, Lee has sued critics for defamation and won.

Lee Kuan Yew died a widower in 2015. Much of the family feud is centered around his will directing to have his house demolished instead of being turned into a museum or heritage site.

All three children, including the prime minister, have publicly supported this. But now the two siblings accused Lee of privately working against their father's will to "enhance his political capital." They said he lobbied a government committee in hopes of preserving the property, built on prime land, in order to "inherit the faith Singaporeans had in Lee Kuan Yew through the visible symbol of the house."

There has been a "misuse of his position and influence over the Singapore government and its agencies to drive his personal agenda," the statement said. "His popularity is inextricably linked to Lee Kuan Yew's legacy. His political power is drawn from his being Lee Kuan Yew's son."

"We do not trust Hsien Loong as a brother or as a leader. We have lost confidence in him," it added. "We fear the use of the organs of state against us and Hsien Yang's wife, Suet Fern."

Lee, who is currently away on holiday, denied the allegations. "I am very disappointed that my siblings have chosen to issue a statement publicizing private family matters. My siblings' statement has hurt our father's legacy," he said in a Facebook post.

"I will do my utmost to continue to do right by my parents. At the same time, I will continue serving Singaporeans honestly and to the best of my ability," Lee added. He plans to "consider this matter further" after the trip.

He also denied the siblings' claim that he and his wife Ho Ching, who is the CEO of the state-owned investor Temasek Holdings, "harbor political ambitions" for their son, Li Hongyi. He said the allegations were "absurd."

A self-proclaimed authoritarian, Lee Kuan Yew was Singapore's first prime minister from 1959 to 1990. He commanded immense respect for turning Singapore into a success story but also fear. He jailed some political rivals without trial for decades and brought defamation lawsuits against journalists and opposition politicians, which had a chilling effect on dissent.

Last April, Lee and his sister disagreed over the host of public programs held to commemorate their father's death. While Lee felt that the events were "generally appropriate," his sister called it "hero-worship" and said that it was something her father stood against.