South Korea has pledged to make "multi-pronged" efforts to secure the release of a tanker seized by Iranian forces on Monday.
The 17,400-dwt Hankuk Chemi (built 2000) and its 20 crew was moved into Bandar Abbas for an alleged breach of pollution regulations.
South Korean owner DM Shipping has denied this.
"What's most important is the security and safety of the people," a spokesman for the office of South Korean president Moon Jae-in said on Thursday.
