A key U.S. official on sanctions policy visited Seoul on Monday as the West gears up for a further economic squeeze on Moscow in the wake of the downing of a Malaysian airliner, officials here said.

Peter Harrell, deputy assistant secretary for counter threat finance and sanctions in the State Department’s economic and business affairs bureau, will hold a briefing session on Tuesday on U.S. sanctions against Russia and Iran for officials from the foreign, finance and industry ministries and banks.

“The visit is part of his regional tour chiefly designed to brief the allies and partners on the Iran sanctions and their impact in light of the extension of nuclear talks, as well as the measures newly levied on Russia recently in the aftermath of the Ukraine crisis,” a senior official at the Foreign Ministry told reporters on customary condition of anonymity.

Harrell’s two-day trip coincides with a move by the U.S. and the European Union to slap new penalties on Moscow, which has supported Ukrainian separatists suspected of having orchestrated the July 17 attack on the Malaysia Airlines jet, killing all 298 passengers on board.

On July 16, the U.S. Treasury imposed a set of stifling sanctions on two major Russian banks, two energy developers and eight defense contractors run by President Vladimir Putin’s confidants.

Washington has been drumming up support from other countries while beefing up its sanctions regime since Russia incorporated Crimea in March.

During his stay, Harrell is likely to request that Seoul join its drive but officials here remain cautious given the country’s strategic interests and partnership with Moscow in initiatives ranging from Eurasian development to the six-nation talks on denuclearizing North Korea.

Another key item on the agenda is international sanctions on Iran, which agreed early this month with the so-called P5+1 ― the U.S., Russia, China, Britain, France and Germany ― to extend the talks on Tehran’s nuclear program until November.

The decision came after the sides failed to meet a July 20 deadline for a long-term accord that would gradually lift sanctions against the Islamic republic in exchange for curbs on its nuclear program.

During the four-month period, Iran will be able to access its frozen oil revenues worth $2.8 billion, while its crude exports are limited to 1 million barrels per day. In return, Tehran is required to continue converting its stockpile of uranium enriched to 20 percent to fuel for a research reactor used to make medical isotopes.

A major consumer of Iranian crude oil, Seoul has sharply reduced its imports in recent years in line with U.S. and EU sanctions.

Harrell is expected to visit China and Japan later in the week.

By Shin Hyon-hee (heeshin@heraldcorp.com)