Lai, 78, was found guilty on all three charges in a national security trial launched after China clamped down on the financial hub to which it had once promised a separate system.

"My father represents everything good about what is, or what at least once was, the financial crown jewel of China -- entrepreneurship, hard work, ingenuity, all of it," Claire Lai, 29, told AFP in an interview in Washington.

"Don't let my father die a martyr in prison. It's going to be a stain on your history that you won't be able to erase," she said.

Claire Lai, who left Hong Kong earlier this year, has joined her brother Sebastien in drawing attention to her father's health.

She said Lai, a diabetic, has been kept in solitary confinement in scorching temperatures, lost significant weight and been deprived of medical care.

The Hong Kong government earlier this month condemned reports, including from AFP, on Lai's treatment as "fact-twisting."

Claire Lai said that while defining what is adequate care may be subjective, the Hong Kong government "did not refute a single one of the substantive health claims I made."

"What the government says or doesn't say, what statement they put out, obviously it's not nice, but it doesn't keep me up at night.

"What does keep me up at night are the images I remember of my father's failing health."

She appealed to authorities to allow her father to have the doctors of his choice and ultimately to release him.

"He is just a good man who loves God, loves the truth, and loves his family, and we just want him back."

Lai, a successful businessman, founded the Apple Daily tabloid that championed democracy in Hong Kong, which Britain returned to China in 1997.

Lai was arrested in late 2020 and has been held ever since. He faces life in prison when he is sentenced.

Jimmy Lai is a citizen of Britain, which condemned the sentence.

The United States did not immediately comment Monday, although President Donald Trump in the past has voiced hope of securing Lai's release.