The South Korean government is to send a delegation to Iran as early as Wednesday night to seek the immediate release of a seized South Korean-flagged tanker. The vessel was captured by Iran's Revolutionary Guard Corps in the Persian Gulf on Monday.
South Korea's vice foreign minister is also scheduled to visit Iran on Sunday.
The Iranian side has criticized South Korea for freezing Iranian funds in bank accounts within the country under US sanctions on Tehran.
Sources close to South Korea's foreign ministry say Seoul and Tehran have been negotiating to use the funds to buy coronavirus vaccines. The sources added the understanding of the United States over the issue has also been obtained.
The Chosunilbo, major conservative South Korean newspaper, on Wednesday quoted diplomatic sources as saying Iran, which cannot trust the US, may have seized the tanker as a way to make sure it can receive vaccines.
Progressive paper Hankyoreh pointed out the possibility that Iran aimed at urging South Korea to buy vaccines on its behalf. It said Iran may have needed diplomatic leverage to secure cooperation from South Korea.
The Iranian authorities claim the tanker violated international law by polluting the marine environment. The tanker operator has denied the allegation.