The United States called on South Korea Monday to add pressure on Iran over its alleged nuclear weapons program, indicating that the Seoul government could soon impose fresh sanctions on Tehran.

The remarks by Robert Einhorn, the State Department‘s special adviser for nonproliferation and arms control, came after the U.S. and several other nations recently announced additional economic sanctions against the Islamic state for its alleged pursuit of nuclear weapons. The measures, targeting Iran’s oil and petrochemical industries and the banking system, followed an International Atomic Energy Agency report that linked Iran‘s uranium enrichment program with nuclear weapons development.

“We’re asking our partners around the world to take additional steps and naturally we are coming to Korea to see what the Republic of Korea can do to sharpen the choice for the leaders of Iran,” Einhorn told a press conference at the U.S. Embassy in Seoul, referring to South Korea by its official name.

“The goal of this pressure is to encourage the leaders of Iran to stop defying the international community and start cooperating to enter into serious and concrete negotiations on Iran‘s nuclear program,” he said.

Einhorn said the U.S. has been in contact with South Korea to discourage imports of petrochemicals, but stopped short of suggesting specific sanction measures.

When asked if Washington has asked Seoul to stop purchases of crude oil from Iran, he said no.

“But let me make a broader point. We would like to see a reduction in Iran’s revenues from the sale of crude oil, and so we would like to discourage countries around the world from continuing to import crude oil in large quantities,” he said.

He added, however, that the U.S. is aware of the tight conditions in the global oil market and the energy needs of countries like South Korea.

“We don‘t want to interfere with those energy security needs.” (Yonhap News)