Even as Italy locked down its northern regions on March 8, Spain’s first coronavirus cluster had already emerged among participants of a funeral service. Mr. Sánchez’s government did not put the country under the highest level of alert and impose a nationwide lockdown until March 14.

Opposition politicians have since charged that it was too late. “Late in comparison with which countries?” Prime Minister Sánchez challenged lawmakers in Congress.

Italy, Britain and France, he noted, declared their own lockdowns only once they had more infections than Spain. He stressed that International Women’s Day, when 120,000 gathered in Madrid on March 8, had also been celebrated on the streets of Brussels, Berlin, Vienna and Paris.

The event has widely been blamed for catapulting the spread of the virus in the capital. Three Spanish government ministers who led the women’s rally later tested positive for the virus, as did Mr. Sánchez’s wife and mother.