By Hyonhee Shin

SEOUL (Reuters) -South Korea’s pro baseball league suspended its season on Monday after five players tested positive for COVID-19, and the country’s toughest anti-coronavirus curbs yet took effect in Seoul to fight a record-setting outbreak.

A mass testing system helped South Korea suffer lower COVID-19 death rates than other developed countries last year, without having to resort to many of the severe lockdown measures that became common elsewhere.

But the country has been setting case records in recent weeks, forcing the government to impose tighter restrictions. The toughest measures yet took effect from Monday in Seoul and neighbouring areas, including a ban on gatherings of more than two people after 6 p.m.

The Korean Baseball Organization (KBO) convened an emergency board meeting on Monday after five players from two teams tested positive for the virus. After hours-long discussions, it decided to suspend the season immediately.

Games were already due to have been paused from July 20 for three weeks to allow players to participate in the Tokyo Olympics, so Monday’s decision means a week of games will be cancelled. The KBO had delayed the start of its season last year due to the pandemic, but this was the first time it suspended play once the season was under way.

South Korea recorded 1,100 new coronavirus cases for July 11, the highest ever recorded on a Sunday, the Korea Disease Control and Prevention Agency (KDCA) said. That followed three consecutive days of peaks leading up to 1,378 on Friday.

The new wave of infections has so far brought fewer serious cases and deaths than earlier rounds, with many older and more vulnerable South Koreans now vaccinated against the virus.

But health authorities have expressed concern over the rising number of young patients who have not yet received vaccine shots, and the spread of the highly contagious Delta variant in recent outbreaks.

In the greater Seoul area, the detection rate of the Delta variant, first detected in India, jumped to 26.5% last week from 2.8% in the second week of June, KDCA said.

KDCA Director Jeong Eun-kyeong said a new study estimated that the number of confirmed daily cases would only start to decline after reaching about 2,300 by mid-August.

If the spread of the infection is strongly controlled, the number of daily cases is estimated to remain at current levels for the next two weeks and then begin to decrease to about 600 cases by the end of August,” Jeong told a briefing on Monday.

The latest outbreak brings South Korea’s total COVID-19 cases to date to 169,146, with 2,044 deaths.

(Reporting by Hyonhee Shin, Aditional reporting by Sangmi Cha; Editing by Muralikumar Anantharaman, Kenneth Maxwell, Gareth Jones and Peter Graff)