Spain on Tuesday reported 261 coronavirus-related deaths in the previous 24 hours, the highest figure it has posted for five and a half months.
The last time the country reported such a high number was on April 25, when 280 people died. The highest number over the past month was on September 22, when 112 people died, according to the Health Ministry.
A ministry spokesman on Tuesday said the sudden jump was likely due to delays in reporting from the country's regions.
Spain has experienced a surge in coronavirus cases in recent weeks, with Madrid a hotspot. More than 40% of the 12,000 new infections reported on Tuesday were in the capital city.
The central government forced Madrid into a strict lockdown on Friday despite opposition from the regional government, banning people from leaving or entering the city without good reason for two weeks.
Nine other areas in metropolitan Madrid are also affected by the lockdown.
Despite the surge in cases, the total number of people who have died in Spain due to the Covid-19 pandemic, at 32,486, is less than in Britain and Italy.