The United States is asking one of its key Asian allies, South

The United States is asking one of its key Asian allies, South Korea, to join it in toughening sanctions against Iran. This comes in response to rising concern about Iran’s nuclear program.

As the United States and countries of the European Union discuss restricting Iran’s lucrative oil exports, other nations are being approached to curtail business relations with Tehran.

The International Atomic Energy Agency of the United Nations last month issued a report outlining more evidence Iran is working to design a nuclear weapon.

Tehran says its nuclear activities are only to generate electricity.

But, since the report, Western nations have taken a series of actions aimed at further isolating Iran. As part of those diplomatic maneuvers, the U.S. State Department’s adviser for non-proliferation and arms control, Robert Einhorn, is in the Republic of Korea this week.

About 10 percent of South Korea’s total oil imports come from Iran.

That accounts for half of the total trade between the two countries. But South Korea is also taking into consideration the close relationship on advanced weapons technology — possibly including nuclear — between Iran and Seoul’s rival neighbor, North Korea.

Another item on Einhorn’s agenda this week is discussions on revising a 1974 agreement between Seoul and Washington on nuclear energy. The accord, which expires in three years, currently prohibits South Korea from reprocessing spent nuclear fuel that could yield plutonium to make nuclear weapons.

Einhorn is among several U.S. government officials visiting Seoul in the next few days for foreign policy discussions.

Another item on Einhorn’s agenda this week is discussions on revising a 1974 agreement between Seoul and Washington on nuclear energy. The accord, which expires in three years, currently prohibits South Korea from reprocessing spent nuclear fuel that could yield plutonium to make nuclear weapons.