A Chinese court has sentenced 10 Hong Kong activists to between seven months and three years in jail for illegally crossing the border, in a case that has drawn international concern over the defendants' treatment.
The group had all faced charges in Hong Kong over anti-government protests in the Chinese-ruled city.
They have been held virtually incommunicado in a mainland prison since their boat was intercepted on 23 August after leaving Hong Kong, allegedly en route to the democratic island of Taiwan.
The court in the city of Shenzhen, which borders the semi-autonomous former British colony of Hong Kong, found eight of the defendants guilty of the illegal crossing and sentenced them to seven months in jail and a 10,000 yuan ($A2012) fine.
Tang Kai-Yin, 31, and Quinn Moon, 33, were found guilty of organising an illegal border crossing and sentenced to three years and two years, respectively, with fines of 20,000 and 15,000 yuan. The court said the pair had acted under the instruction of others, suggesting more arrests could follow.
The defendants' family-appointed lawyers, who were denied access to their clients, and rights groups criticised the legal process.
"These sentences meted out after an unfair trial lay bare the dangers faced by anybody who finds themselves tried under the Chinese criminal system," Amnesty International's Asia-Pacific Regional Director Yamini Mishra said in a statement.
"This group of young Hongkongers will be at risk of torture and other ill-treatment in Chinese jails."
All 10 had pleaded guilty to their crimes, the court said. The defendants all appeared for the verdicts and were taken away afterwards.
Mainland authorities appointed lawyers for the defendants but they were not available for comment.
Two minors who were among the 11 males and one female - aged 16-33 at the time of their detention - had pleaded guilty to illegal border crossing and would not be charged, the prosecutor said.
After the verdicts were announced, Hong Kong police said that the two youngest of the group, now aged 17 and 18, had been handed over to authorities and would appear in court in the financial hub after completing quarantine for coronavirus.
"Hong Kong police want to reiterate the seriousness of absconding; society will not tolerate criminals who are waiting for court hearing but choose to abscond," said Cheng Lai-ki, acting chief superintendent of the commercial crime bureau.
The 10 who were sentenced could face additional charges on their return to Hong Kong, she added.
The scene outside the court was quiet, with few media present and no diplomatic representatives after they were denied access to a hearing for the 10 on Monday.
Relatives of the defendants say they were denied access to independent lawyers and their repeated requests to visit the group were denied.
Diplomatic representatives from countries including the US, Britain, Canada and Australia, were not allowed to enter the hearing at Kantian District People's Court on Monday after authorities said the court was full.
The US and European Union have called for the 12 to be released and allowed to return to Hong Kong.
