Thailand confirmed 121 new infections of the novel coronavirus, a senior official said on Sunday, up from the 103 cases reported earlier in the day.
Taweesin Wisanuyothin, a spokesman for the country's COVID-19 pandemic taskforce, said at a briefing that the new cases include 94 domestic transmissions and 18 in migrant workers connected to an outbreak at a seafood market in Samut Sakhon, a province southwest of Bangkok.
Infections connected to this cluster have spread to 38 provinces.
Some 36 local infections were in Rayong province linked to a gambling den, the spokesman said.
"The numbers reflect a heavier (outbreak), but we have more knowledge and capacity," he said, adding that authorities were ready to handle the increased numbers.
Eight new cases were found in state quarantine facilities, and one infection in a person coming from abroad who did not enter quarantine.
Thailand has reported a total of 6,141 cases and 60 deaths.
Meanwhile, South Korea reported 970 new coronavirus cases for Saturday, the Korea Disease Control and Prevention Agency (KDCA) said on Sunday, bringing the national tally to 56,872 cases, with 808 deaths.
That is the smallest in five days but still not far off from the record 1,241 infections logged on Friday.
The government plans to hold a meeting on Sunday when it may tighten distancing rules to the toughest level for the greater Seoul area.