Iran's President Hassan Rouhani has appealed for a Korean Peninsula free of nuclear weapons during a visit to Tehran by his South Korean counterpart, the official IRNA news agency reports.
Rouhani met with South Korean President Park Geun-hye on Monday and said Iran seeks a world free of weapons of mass destruction, "especially nuclear" weapons.
"Our demand is a world free of weapons of mass destruction, especially freeing the Korean Peninsula and the Middle East from destructive weapons," he said.
Park said she has asked for Iran's help in implementing UN Security Council resolutions calling for the nuclear disarmament of the Korean Peninsula.
The remarks were aimed at North Korea, which has been hit with tough UN sanctions over its nuclear weapons program. North Korea has conducted four nuclear bomb tests and tested a long-range rocket earlier this year.
Park arrived in Tehran on Sunday for the first visit by a South Korean president to Iran since 1962.
Rouhani said both sides agreed to increase their bilateral trade from the current $US6 billion ($A7.9 billion) per year to $US18 billion ($A23.7 billion) in the coming years. They also signed a number of agreements in the fields of oil and gas, railroads, tourism, and technology, and agreed to re-establish direct flights between Tehran and Seoul.
Iran has been seeking to reintegrate into the global economic system since nuclear-related sanctions were lifted in January under a landmark deal with world powers.
Energy-hungry South Korea, the world's fifth largest importer of crude oil, used to be one of the biggest buyers of Iranian oil before the sanctions were imposed.
Iran said it has raised its oil and gas condensate exports to South Korea to 400,000 barrels per day, a fourfold increase since the nuclear deal was implemented.
South Korea and Iran established diplomatic ties in 1962 but their heads of states have never held bi-lateral talks.
Also on Monday, Iran's Supreme Leader Ayatollah Ali Khamenei, who has final say on all state matters, told Park that the Seoul-ally United States should not influence the extent of Iran-South Korean ties.
"Relations between Iran and South Korea should not be dependent on sanctions or influenced by the United States or any grudges US may hold" against Iran, Khamenei's website cited the top cleric as saying.
"We believe there is a possibility for more understanding, agreement and cooperation with Asian countries, including South Korea," Khamenei also said.