South Korea reported 599 new cases of the coronavirus on Monday, bringing the total number to 4,335, with most of them continuing to occur in the southeastern city of Daegu, the epicenter of the nation's outbreak.

The death toll rose to 26, up from 22 as of the end of Sunday, according to the country's Centers for Disease Control and Prevention.

With most confirmed cases of infection in Daegu being linked to a minor Christian group known as Shincheonji Church of Jesus, the head of the sect apologized to the public on Monday at his first public appearance since the outbreak.

"I'd like to say words of deep regret to all the people," Lee Man Hee said while kneeling at a press conference near a sect facility in Gapyeong, a county in the country's north.

Lee said that although it was unintentional, he feels sorry that the virus has spread to so many people. He also expressed gratitude to the government for putting forth its utmost effort in tackling the epidemic.

Lee vowed to give his full support, in terms of both human resources and financial aid, in close cooperation with the government.

Mass transmissions are believed to have occurred among sect members during a service at the group's church in Daegu.

The Seoul municipal government filed a criminal complaint on Sunday, accusing the sect's senior officials, including Lee, of murder and other crimes.

The complaint, filed with prosecutors, alleges that the group failed to cooperate in preventing the spread of the virus.

After reporting 476 additional cases earlier Monday, the Health and Welfare Ministry added 123 new cases in the afternoon.

Of the 476 cases, 377 were in Daegu, the nation's fourth-largest city, while 68 were in neighboring North Gyeongsang Province, according to a ministry statement.

The government decided Sunday to change hospitalization rules to take in as many COVID-19 patients as possible to provide in-hospital care to those who are self-quarantining at home after being found infected with the virus.

More than 1,600 people have been at home waiting to be hospitalized after they tested positive, and the rule change takes effect on Monday, Prime Minister Chung Sye Kyun told reporters in Daegu in the morning.

A medical center capable of accommodating 160 people with light symptoms is slated to open in Daegu on Monday, with a similar facility also being planned in North Gyeongsang.

In Seoul, officials of the government and the ruling Democratic Party agreed to draw up a supplementary budget worth 6.2 trillion won ($5.2 billion) to help shore up the economy, which has been blunted by the effects of the coronavirus.

The budget is expected to be submitted to parliament by the end of this week.

Also Monday, Education Minister Yoo Eun Hae said the start of the new school year for all elementary, junior high and high schools will be postponed for another two weeks until March 23, due to worries over the virus. The ministry had postponed the start by one week until Monday.