Seoul, April 9 : The Foreign Ministry in Seoul said on Friday that Tehran has released a South Korean oil tanker that was detained at an Iranian port since January 4. The ship and its captain's 's release came after the remaining 19 sailors of the MT Hankuk Chemi were set free on February 2, according to the Ministry. The captain had remained in the vessel for the tanker's management, reports Xinhua news agency. The Ministry said in a statement that it had called for the rapid release via close communications with the Iranian foreign authorities after the South Korean Vice Foreign minister's visit to Tehran in January. It noted that the captain and the sailors were healthy with the vessel being in a good condition. The South Korean ship was seized by Iran's military in early January due to an alleged chemical pollution. On board the vessel were 20 sailors, including five South Koreans, 11 Myanmar nationals, two Indonesians and two Vietnamese. /IANS