By Michael R. Gordon 

The Trump administration threatened Wednesday to impose an array of fresh sanctions to deter China and Russia from selling weapons to Iran after an arms embargo on Washington's Middle East foe expires next month.

Elliott Abrams, the administration's new special envoy for Iran and Venezuela, told reporters that the sanctions "will have a very significant impact" on arms manufacturers and traders that seek to do business with Tehran. Details of the sanctions will be made public Monday, he said.

The administration's stance has been viewed skeptically by some former government sanctions officials who say that China and Russia are likely to refrain from shipping arms to Iran as they wait to see whether Mr. Trump is re-elected, and that some of the new U.S. sanctions may be duplicative.

The administration's plan for new sanctions is the latest twist in its Iran policy, which has left the U.S. isolated on that issue in the United Nations Security Council and at odds with some of its closest European allies.

At first, U.S. officials sought to persuade the U.N. Security Council to extend an international arms embargo on Iran, which is due to expire on Oct. 18 and which was part of the 2015 nuclear deal between Iran and six world powers.

After that bid was rejected last month by the Security Council, U.S. officials sought to invoke a legal process that would reimpose all of the sanctions that were in place before the Iran deal was concluded.

That maneuver, known as a "snapback" of sanctions, was rebuffed by European nations, Russia and China, who are still parties to the Iran accord and assert that the U.S. forfeited its legal right to seek the reimposition of sanctions by withdrawing from the Iran accord two years ago.

The Trump administration still insists its legal analysis is correct and says international sanctions are to be formally reimposed on Saturday night.

Having failed at persuasion, however, the U.S. is turning to pressure: The threat of sanctions against Chinese and Russian companies that sell, finance or ship arms to Iran and, potentially, any foreign companies that do business with them.

Some sanctions experts question whether the new U.S. measures will have any effect in the next several months.

"I don't think it will change the price of tea," said Richard Nephew, who served as the lead sanctions expert on the U.S. team that negotiated the Iran deal during the Obama administration.

He said that China and Russia would be unlikely to undertake any major weapons shipments to Iran while they assess how the November presidential election might alter U.S. policy toward Tehran. He also said that the Russian defense sector is already subject to sanctions.

But Richard Goldberg, a senior adviser at the Foundation for Defense of Democracies, which has supported the Trump administration's tough line on Iran, argued that the new sanctions could be effective and build on existing measures.

"If a Russian or Chinese defense firm tries to sell weapons to Iran, that firm and all the supporting institutions involved in a transaction would face secondary U.S. sanctions," Mr. Goldberg said. "It all depends on how and if sanctions are enforced."

European diplomats have said that they favor some sort of compromise arrangement to preclude the sale of new weapons to Iran and the provision of arms by Tehran to its regional proxies.

European nations abstained on the U.S. motion in the Security Council to extend the arms embargo because they concluded it would have no chance of passing in the face of Russian and Chinese vetoes and feared the Trump administration's ultimate goal is to dismantle the 2015 Iran accord, which they want to preserve.

The European Union has its own embargo on arms sales to Iran, which continues through 2023.

Joe Biden, the Democratic candidate for president, favors returning to the 2015 Iran nuclear accord on the condition that Tehran begins to abide by the limits established by the agreement. Mr. Biden has also said that he would try to negotiate a tougher, follow-on accord, though he hasn't said what its provisions might be.

--Laurence Norman in Brussels contributed to this article.

Write to Michael R. Gordon at michael.gordon@wsj.com

(END) Dow Jones Newswires

September 16, 2020 19:13 ET (23:13 GMT)