Seoul, Nov 25 : South Korea's new coronavirus cases fell below 4,000 on Thursday, a day after hitting an all time-high of 4,115. But critical cases and deaths climbed to fresh highs, fueling worries about the virus spread ahead of another pandemic winter. The country reported 3,938 new Covid-19 cases, including 3,917 local infections, raising the total caseload to 429,002, Yonhap news agency reported, citing the Korea Disease Control and Prevention Agency (KDCA). Critically ill patients hit an all-time high of 612, up 26 from the previous record set a day earlier. The same figure averaged 498 for the seven days ending Sunday. The country added 39 more deaths from Covid-19, the highest number since the start of the fourth wave of the pandemic in July, bringing the death toll to 3,401, with the fatality rate standing at 0.79 per cent. /IANS