The South Korean presidential office says it will make multifaceted efforts to win the swift release of a South Korean oil tanker seized by Iran’s Revolutionary Guards. 

A key presidential official relayed the position in a meeting with reporters on Thursday, adding what matters most is the safety of South Korean citizens. 

The official added all 20 crew members of the MT Hankuk Chemi were confirmed to be safe and healthy. 

The South Korean Foreign Ministry earlier said three employees from the South Korean Embassy in Tehran conducted a consular interview the previous day with one of the five South Korean members aboard the tanker and confirmed the safety of all. Eleven Myanmar nationals, two Indonesians and two Vietnamese were also on board when the South Korean-flagged vessel was captured in the Strait of Hormuz on Monday. 

Regarding a media report that Iranian President Hassan Rouhani sent a letter to President Moon Jae-in twice, the official said facts are being verified but added that letters between top leaders might not be disclosed out of consideration for the other country involved. 

The Hankyoreh newspaper on Thursday quoted a diplomatic source with knowledge of Seoul-Tehran relations as saying Rouhani sent two letters to Moon over the past two years or so calling for a solution to the freezing of seven billion dollars in Iranian oil money at South Korean banks due to U.S. sanctions. 

The local daily said the presidential office replied to each letter but Tehran was disappointed by the lack of practical measures on Seoul’s part to resolve the issue. 

Speculation is rising that Iran’s seizure of the South Korean vessel is to gain the upper hand in negotiations on the frozen funds, but the Iranian government has claimed they are separate issues, attributing the seizure to alleged environmental guideline violations.