The ruling Democratic Party (DP) said it is exploring ways to transfer former Prime Minister Lee Hae-chan to South Korea after his health sharply deteriorated during a trip to Vietnam, leaving him in critical condition.

Party Secretary-General Jo Seoung-lae told reporters at the National Assembly on Sunday that Lee had not appeared to regain consciousness and that local conditions made further medical treatment difficult, necessitating an emergency transfer.

Jo said an air ambulance would be required but noted that such services are not available in Vietnam, stressing the urgency of arranging Lee's return to South Korea.

Cho Jung-sik, special adviser to the president for political affairs, who is currently in Vietnam, is reportedly discussing transfer options with DP lawmakers and Lee's family.

Lee, who serves as executive vice chairperson of the Peaceful Unification Advisory Council (PUAC), collapsed during an official visit to Ho Chi Minh City on Friday after experiencing breathing difficulties.

He was taken to a local hospital, diagnosed with a myocardial infarction, and underwent a stent insertion procedure. The former prime minister reportedly remains in critical condition and is breathing with the assistance of a mechanical device.