South Korea has been struggling to cope with the epidemic, with the total number of infections reaching 50 since its first outbreak in on May 21. Four patients have died, while more than 1,800 people with suspected symptoms have been isolated or ordered to remain in self-quarantine.

"I'd like to express regret over causing huge concerns to the people over a continued increase in the numbers of confirmed cases and those quarantined," Choi said while presiding over a meeting of relevant Cabinet ministers to devise government measures against MERS.

The government has come under intense public and media fire for its poor initial responses to the disease. President Park Geun-hye called a meeting of relevant government officials to discuss the situation as late as 14 days after the first patient was reported.

"Keeping in mind the fact that priority is to contain the spread of the virus and eradicate it as soon as possible, each ministry should employ every possible means," Choi said, vowing that the government would provide extra budgets, if necessary.

Choi also called for close cooperation among relevant ministries as well as between the central and local authorities, a thinly-veiled accusation against Seoul Mayor Park Won-soon who openly criticized the central government on Thursday for not doing enough to contain the virus.

Choi cut short his overseas trip and returned home earlier in the day. He, as the finance minister, visited France and Britain and attended a ministerial meeting of the Organization for Economic Cooperation and Development, of which South Korea is a member.

He became the acting prime minister after former Prime Minister Lee Wan-koo resigned in late April under pressure for alleged involvement in a corruption scandal. Choi stands third in government hierarchy behind the president and the prime minister. (Yonhap)