TEHRAN— South Korea's vice foreign minister made back-to-back phone calls Friday with top U.S. and European Union negotiators involved in talks aimed at reviving the 2015 Iran nuclear deal, according to his office.

First Vice Foreign Minister Cho Hyun-dong spoke on the phone with U.S. special envoy for Iran Robert Malley and EU mediator Enrique Mora to discuss the latest developments in negotiations to resurrect the Joint Comprehensive Plan of Action (JCPOA), according to the ministry.

During the phone conversation, Cho reaffirmed Seoul's support for the JCPOA and voiced hope that an agreement may help resolve South Korea's outstanding problems with Iran, according to the ministry.

Relations between Seoul and Tehran remain strained over $7 billion in Iranian fund held in two Korean banks under U.S. sanctions reimposed after then-U.S. President Donald Trump withdrew from the nuclear agreement in 2018. Tehran has long demanded that Seoul release the fund.