The White House has said that three US citizens Washington considered wrongfully detained in China have been released and are returning home.

The US on Wednesday identified the three citizens as Mark Swidan, Kai Li and John Leung, who had all been imprisoned for years in China.

Swidan had faced a possible death sentence on drug charges, while Li and Leung had both been accused of espionage.

“Soon they will return and be reunited with their families for the first time in many years,” the White House said in a statement.

The agreement comes in the final days of the Biden administration before President-elect Donald Trump takes office in January of next year.

Biden has continued many aspects of the hard line that Trump took towards China during the Republican’s first term from 2017 to 2021. But while tensions have remained, particularly over strengthened US ties with allies in Asia Pacific and support for Taiwan, the outgoing president has maintained steady relations with Chinese leader Xi Jinping.

Trump’s pledges to surge tariffs on China, meanwhile, have prompted warnings that ties between the two economic superpowers could soon strain.

The White House did not immediately confirm a report by the Politico news site that the release was part of a prisoner swap.

Instead, a US official told reporters that the Biden administration had raised the cases in multiple meetings with Chinese officials over the past several years. That included Biden’s meeting with Xi on the sidelines of the annual Asia-Pacific Economic Cooperation summit in Peru earlier this month.

Li, who had immigrated to the US from China and started an export business in the US, had been detained in September 2016 after flying into Shanghai. He was accused of providing state secrets to the FBI.

A UN working group had previously called his 10-year prison sentence arbitrary and his family has claimed his detainment was politically motivated.

Leung was detained in 2021 by the local bureau of China’s counterintelligence agency in the southeastern city of Suzhou amid the COVID lockdown.

The US Department of State had categorised all three as wrongfully detained.