In a striking speech before thousands of North Koreans, leader Kim Jong-un’s sister said he suffered a fever while guiding the country to victory over the coronavirus. She blamed rival South Korea for the outbreak and vowed “deadly” retaliation.

Kim Yo Jong, a powerful official in charge of inter-Korean relations, glorified her brother’s leadership during the outbreak in her speech Wednesday at a national meeting where he jubilantly described the country’s widely disputed success over the virus as an “amazing miracle” in global public health.

“Even though he was seriously ill with a high fever, he could not lie down for a