Eighteen people have died from the coronavirus outside of hospitals in Japan’s Osaka Prefecture, officials reported, amid calls for more stringent curbs on movement to halt a 4th wave of infections ahead of the Olympics.

All but one of the fatalities occurred since March 1 as highly infectious strains of the virus triggered a surge in new infections, the prefecture said late on Monday for the first time. Most were 60 years old or more, but one death was in their 30s.

On Friday, Japan extended a state of emergency for much of the country in a bid to contain the 4th wave of the pandemic, with the start of the Tokyo Olympics a little more than 2 months away.

The declaration covers Tokyo, Kyoto, Osaka, and Hyogo prefectures, including around a quarter of Japan’s population, and is set to last until May 31.

The Kyodo news agency reported that some prefectural governors called for tougher emergency measures to be enforced nationwide at an online meeting on Monday.

The region of Osaka has been particularly hard hit, and it has become the epicenter of infections from the variant first identified in Britain that is more infectious and causes more serious conditions. Over 96% of Osaka Prefecture’s critical care hospital beds are now occupied.

Osaka Prefecture reported 668 new infections on Monday while Tokyo had 573.