Authorities suspected the man, who had entered the country on a ship crew visa, intended to illegally stay in South Korea, as there had been several similar incidents involving Vietnamese nationals in recent month, officials said.
Every person arriving in South Korea from overseas is required to undergo two weeks of isolation to prevent the spread of the new coronavirus regardless of whether they have Covid-19 symptoms.
In March, the country’s health ministry warned it would deport foreigners and South Korean citizens could face jail for violating self-quarantine rules after a surge in imported coronavirus cases.
The Korea Disease Control and Prevention Agency (KDCA) reported 114 new infections on Tuesday midnight, bringing the national tally to 24,353 cases, with 425 deaths.