Brazil’s coronavirus cases have spiked to 135,106 including 9,146 deaths, according to numbers released Wednesday by the Brazilian Health Ministry. This surge comes as President Jair Bolsonaro’s spokesman, Gen. Otavio Santana do Rego Barros, confirmed he tested positive for Covid-19.

Yet Bolsonaro said earlier this week he believed “the worst had passed” for the coronavirus pandemic, during a press conference outside the Alvorada presidential residence in Brasilia. But as the number of cases and deaths continue to climb, many health experts fear the worst is yet to come.

Since Bolsonaro made the comment in Brasilia on Tuesday, there have been more than 20,000 new cases of coronavirus and the country registered 610 deaths on Thursday, nearly the highest toll yet in a 24-hour period, according to the Health Ministry.

Health Minister Nelson Teich said Thursday that stricter lockdowns may be needed in some of the hardest-hit regions, during a video conference with members of the lower house of Congress.

Former Health Minister Luiz Henrique Mandetta said “the toughest months” are likely to be May and June, during an interview with TV Globo last month, four days before he was fired by Bolsonaro over disagreements on the country’s coronavirus strategy.