South Korean firms Korea Midland Power Co (KOMIPO), Korea Southern Power Co (KOSPO) and SK subsidiary PRISM Energy International have issued a tender for one liquefied natural gas (LNG) cargo for delivery in June.According to a tender issued by KOMIPO, which is leading the tender process, the buyers are seeking 3-3.6 trillion British thermal units (Btu) of LNG on a JKM-linked and delivered ex-ship (DES) basis.The cargo is to be delivered on June 12 or June 23 to one of the Kogas-operated terminals in Incheon, Pyeongtaek, Tongyeong and Samcheok in Korea.The JKM, or Japan-Korea-Marker, is the LN