SEOUL, South Korea — Christmas Day has brought South Korea its biggest daily increase in coronavirus infections of the pandemic as officials urged for citizen vigilance to help curb a viral surge that has worsened hospitalization and deaths.

The 1,241 new confirmed cases reported Friday raised the country’s total to 54,770. Officials said 17 more people had died from COVID-19 in the previous 24 hours, bringing the death toll to 773.

The country has been expanding its mass testing program to slow the rate of transmissions and more than 118,000 tests were conducted Thursday alone. Officials are also clamping down on private social gatherings through Jan. 3, shutting down national parks and ski resorts and setting fines for restaurants if they serve groups of five people or more.