US Secretary of State Mike Pompeo assailed the Chinese government on Thursday and called authorities in Hong Kong “lackeys” for the treatment of a group of fugitives known as the “Hong Kong 12”.

Ten individuals, who authorities arrested at sea as they fled the city and tried to reach Taiwan by speedboat in August, were sentenced from seven months to three years in prison by a Shenzhen court on Wednesday; two underage passengers were handed over to Hong Kong police.

“Hong Kong was a thriving territory until the Chinese Communist Party and its local lackeys destroyed its rule of law and eviscerated the Hong Kong people’s freedoms,” Pompeo declared.

“The ‘Hong Kong 12’ who tried to flee this tyranny deserved a hero’s welcome abroad, not capture, a secret trial and prison sentences. The United States strongly condemns the Shenzhen court’s actions and calls for the 10 members of the group who were sentenced to jail terms to be immediately and unconditionally released.”

Pompeo’s statement joined an earlier call by the European Union for the fugitives’ return to Hong Kong. It was also the latest in a series of remarks he has made criticising Hong Kong and Chinese government officials for their moves against pro-democracy activists and opposition lawmakers in the semi-autonomous Chinese territory, after Beijing imposed a controversial national security law on the city in June.

The law criminalises a broad range of behaviours under the four categories of secession, terrorism, subversion and collusion with foreign powers. Opposition politicians and critics warn it could be used to suppress dissent and erode freedoms in the city.

In August, the US imposed economic sanctions on 11 current and former Chinese officials, including Hong Kong’s chief executive, Carrie Lam Cheng Yuet-ngor, following an executive order by US President Donald Trump that revoked Hong Kong’s special trade status and distinct from the.

Eight of the 12 fugitives were accused of illegally crossing the border, and two – Tang Kai-yin and Quinn Moon, the sole woman in the group – were charged with organising the crime. Tang was sentenced to a three-year prison term, while Quinn received two years. The other eight were each jailed for seven months.

All but one of the 12 fugitives, aged 16 to 33, had already been charged in Hong Kong with offences arising from last year’s anti-government protests. Activist Andy Li has not been formally charged, but was arrested in August on suspicion of money laundering and collusion with foreign forces, an offence under the Beijing-imposed national security law.

“The CCP’s persecution of the Hong Kong 12 – two of whom were juveniles at the time of their arrest – exposes once again Beijing’s brutality, blatant disregard for the international treaties it has signed, and its disdain for the rights of the Hong Kong people,” Pompeo said.