Taiwan reported 22 new coronavirus cases on Sunday, almost all of them sailors who were on a navy visit to the small Pacific islands state of Palau, which said there was "little chance" it was the source of the infection.
Taiwan's government on Sunday said 700 navy personnel were being quarantined and tested and there were 24 positive cases altogether. Of those, three cadets had been to Palau, one of only 15 countries to maintain formal diplomatic ties with Taiwan, and one of the last states in the world yet to report a coronavirus outbreak.
Taiwan Health Minister Chen Shih-chung said cases were discovered on one of the three ships that visited Palau from March 12-15 but further investigations were needed before they could determine where exactly they were infected.
Taiwan has to date been relatively successful at controlling the novel coronavirus through a focus on early prevention and detection.
Palau closed its borders as a pre-emptive measure a month ago as cases rose sharply among its neighbours.
Palau Health Minister Emais Roberts said on Monday the government would stay in touch with Taiwan during its investigation into the outbreak, which was most likely a "ship cluster" contained within that vessel.
More than a month had passed since the ships visited, he said, and no-one in Palau has tested positive or shown any symptoms of the coronavirus.
"There is little chance that the virus on the vessels came from Palau," he said in a statement. "There is no reason for us in Palau to panic."
Palau last week started its own domestic testing programme with the help of Taiwanese lab experts and equipment purchased from Taipei and transported by fishing boat.
In an interview with Reuters, Palau President Tommy Remengesau said he was prepared to keep borders closed for "as long as necessary" to keep the virus out of the country of 20,000 people.
Mei Chia-shu, deputy navy commander, gave a deep bow on Sunday in an expression of apology for the infections and for not properly carrying out prevention measures.
President Tsai Ing-wen had been at the ceremony to welcome back the ships but had only waved to the sailors from the shore and had not been exposed, her office said.
Taiwan on Monday reported two new cases of the coronavirus, taking the number of infections to 422, with six deaths.