Iran's central bank has submitted a letter of intent(LOI) for ​Investor-State Dispute Settlement(ISDS), requesting South Korea to return its frozen assets locked in Korean banks. 

According to a foreign ministry official in Seoul on Friday, the government received the LOI last September and has been seeking to resolve the dispute over Iran's frozen assets under U.S. sanctions.

If the two countries fail to find any solution through negotiations within six months after the LOI  was accepted, Iran may file an Investor-State Dispute(ISD) suit.

The frozen asset issue started in 2018 when former U.S. President Donald Trump withdrew from a 2015 nuclear deal and reinstated economic sanctions against Iran.