The Pacific island nation of Vanuatu has detained two Chinese fishing boats and a Russian yacht due to concerns the vessels were operating illegally in its waters, police said.
It is believed to be the first time authorities in Vanuatu have detained Chinese fishing vessels.
The Chinese boats, Dong Gang Xing 13 and 16, were apprehended by a police patrol boat on January 19 near Hiu island in Vanuatu's northern waters, according to police.
The boats are currently moored in Port Vila, as 14 Chinese nationals undergo Covid-19 quarantine before being questioned on suspicion of illegal fishing.
While accompanying the Chinese vessels back to the capital, the patrol boat also spotted a Russian yacht near Luganville, police said.
Three Russian nationals on board were detained and will also face questioning over their presence near Vanuatu's second-largest city.
The arrests come as China's fishing activities in the Pacific are in the spotlight after Palau detained another ship last month.
While Palau has a tense relationship with China due to its diplomatic recognition of Taiwan, Vanuatu is an ally of Beijing and receives substantial aid from the Asian superpower.
A report from London-based research centre the Overseas Development Institute last year found China had the largest distant-water fishing fleet in the world, estimated at almost 17,000 vessels.
It named China as "the most significant actor" in illegal fishing worldwide, citing poor governance of the fleet and a failure to follow sustainable practices.
Beijing denies the accusations, with a foreign ministry spokeswoman saying in December: "As a responsible fishing country, China adheres to the path of green and sustainable development."
Vanuatu closed its air and maritime borders last March in response to the Covid-19 pandemic, amid fears its limited health care system would be unable to cope with an outbreak of the virus.
It has so far managed to keep coronavirus out of the community, recording only one case in quarantine in November.
The Chinese embassy in Port Vila did not respond to requests for comment.