Washington, United States US lawmakers on Wednesday vowed to keep up pressure to free Hong Kong pro-democracy media tycoon Jimmy Lai, whose son warned that time was running out.

Lai, the founder of the now-shuttered popular Chinese-language tabloid Apple Daily which supported mass pro-democracy protests, was detained in 2020 and is standing trial on charges including sedition and colluding with foreign forces.

At a press event held by the US Senate Foreign Relations Committee, his son said Lai, 76, was struggling in solitary confinement inside a cell that is 38 degrees Celsius (100 Fahrenheit).

“Make no mistake — they are killing him because of his commitment to democracy,” Sebastian Lai said.

“My dad is also someone who is living out the duty of the free — the duty to fight and protect freedom whenever and wherever it is being threatened,” he said.

“I call on those who understand the same duty to act now and to save him before it’s too late,” he said.

Former House speaker Nancy Pelosi told him, “Sebastian, your father is a hero to us.”

Pelosi said authoritarian states hope to convince prisoners that they are forgotten.

“We are saying to the world, to the Chinese government, to the Chinese Communist Party, that we know — not only do we remember, we exalt, we lift up, the sacrifice of Jimmy Lai,” Pelosi said.

Senate Foreign Relations Committee Chairman Ben Cardin, calling Lai a symbol of the “vibrant, free community” that Hong Kong once was, vowed to keep a spotlight to free Lai as well as less prominent people detained under a harsh new security law in Hong Kong.

Lai pleaded not guilty in the trial that began in January. He faces charges that could carry life imprisonment.

Prosecutors have sought to make a case against him by showing his media appearances and have named former US secretary of state Mike Pompeo among his foreign contacts and “agents.”

China promised a separate system for Hong Kong before the financial hub’s handover by Britain in 1997 but clamped down hard after the massive and occasionally violent pro-democracy protests in 2019.