In a surge that sent a shock wave throughout the nation, Tokyo recorded 366 new COVID-19 cases Thursday, topping the 300 mark for the first time and leaping more than 100 cases from the previous day.

It was by far the highest single-day figure ever recorded by the metropolis. It will likely stoke concerns of a second wave and heap further pressure on policymakers to reinstate some of the earlier restrictions, including issuing business closure requests and declaring a state of emergency.

“It’s a significant number,” Tokyo Gov. Yuriko Koike told a group of reporters Thursday. “I think we can consider this to be a warning that stronger public cooperation is needed” to curb the contagion.