The latest wave of COVID-19 infections is showing no signs of slowing down, with 1,540 new cases announced Tuesday -- 1,476 locally transmitted and 64 imported from overseas.

The figure, which covers the 24 hours ending Monday at midnight, pushes the total number of cases to date to 213,987, according to the Korea Disease Control and Prevention Agency. South Korea added nine more deaths, raising the death toll to 2,134.

The virus seemed to have slowed down a little in the capital region -- Seoul, Incheon and Gyeonggi Province -- thanks to strict social distancing rules, but the situation has become more severe in other parts of the country.

Seoul, Incheon and Gyeonggi Province accounted for 55.4 percent of newly reported locally transmitted cases. Gyeonggi Province reported 398 new cases, followed by Seoul with 356 cases and Incheon with 64.

At the same time, Busan reported 105 new cases and neighboring South Gyeongsang Province added 110 new cases, showing that the virus situation is serious in other regions as well.

Korea is enforcing Level 4 social distancing rules in the Greater Seoul area until Aug. 22, and most of the other regions within the country are under Level 3 rules. Authorities have additionally banned gatherings of three or more people after 6 p.m. and maintained 10 p.m. curfews for most businesses.

While the restrictions are to remain in place for less than two weeks, experts have said the worst is yet to come, as variants of COVID-19 will continue to spread, especially when combined with increased travel in the summer vacation season.

Dr. Chun Eun-mi, a respiratory disease specialist at Ewha Womans University Medical Center, warned that the number of daily cases could exceed 2,000 in the coming days, as the delta variant is expected to have spread quickly among vacationers.

“If the number doesn’t reach 2,000, I would say that’s because the number of tests was low,” Chun said in a radio interview Tuesday. “Once we go past that 2,000 mark, the number could rise at an even faster rate, and now that the holiday season is over, those who return home will now undergo testing.”

Authorities on Tuesday strongly encouraged people returning from vacation to take COVID-19 tests as needed, adding that they would install more testing centers at highway rest stops.

Older adults are likely to be at risk of infection with the delta variant, Chun added, because time has passed since they received their vaccinations in February and March and their immunity may have waned.

Korea is carrying out a national vaccination program, and people aged between 18 and 49 could begin booking appointments Monday night.

Around 21.37 million people, or 41.6 percent of Korea’s 51.3 million people, have received their first COVID-19 shots, and close to 7.9 million people have been fully vaccinated since the country started the nationwide program in late February.

But the country faces a vaccine supply shortage after Moderna failed to provide the planned doses of COVID-19 vaccines for this month.

Moderna will be sending less than half of the roughly 9 million doses of the vaccine it promised to ship this month, and in response Korea has lengthened the interval between the first and second doses of two messenger RNA COVID-19 vaccines to six weeks instead of the recommended three to four weeks.

The country also approved plans Tuesday for the first-ever Phase 3 clinical trial for a locally developed COVID-19 vaccine. SK Bioscience plans to run a comparative clinical study on its COVID-19 vaccine candidate and that made by AstraZeneca, and intends to start recruiting participants in the coming weeks.