U.S. Vice President Mike Pence says the U.S. will keep up pressure on Iran as Tehran threatened that it may restart its deactivated centrifuges and increase its enrichment of uranium to 20 percent purity as it continues to move away from a 2015 nuclear agreement that Washington abandoned last year.
Pence said in a speech on July 8 to a pro-Israel Christian organization in Washington that the U.S. would "never allow Iran to obtain a nuclear weapon."
Iran has said repeatedly that all its nuclear activities are aimed at peaceful purposes.
Pence said that Iran should not "confuse American restraint with a lack of American resolve."
"We hope for the best, but the United States of America and our military are prepared to protect our interests and protect our personnel and our citizens in the region," he said.
In his prepared remarks, the U.S. vice president said that Washington was willing to talk with Iran but "America will not back down" but he did not say that in his speech.
Pence noted that Iran said it has begun enriching uranium beyond limits set by the 2015 nuclear agreement. He said it was part of the Islamic republic's "malign" activities.
The enrichment threats made on July 8 by Behrouz Kamalvandi, the spokesman for Iran's Atomic Energy Organization, would go far beyond the measures Iran took during the previous week to increase its stocks of fissile material just beyond the limits allowed under the 2015 nuclear deal.
Weapons-grade uranium usually has an enrichment level of 90 percent, but a nuclear weapon theoretically could be built with hundreds of kilograms of material enriched to 20 percent purity -- a level that is considered to be "weapons-usable."
Enriching uranium at 20 percent is also considered to be a short technical step away from reaching levels of 90 percent weapons-grade material.
Kamalvandi's remarks came as he announced on July 8 that Iran had enriched uranium beyond the 3.67 percent purity level allowed under its 2015 nuclear deal with world powers -- passing the 4.5 percent level.
Kamalvandi suggested that Tehran could increase its uranium enrichment to 20 percent purity as part of a third step away from the nuclear deal.
He said that Iran does not currently need to enrich the fuel at 20 percent, however.
The UN says Secretary-General Antonio Guterres believes Iran's uranium enrichment above the limit set in the 2015 nuclear accord, if confirmed, would neither help preserve the agreement "nor secure tangible economic benefits for the Iranian people."
UN deputy spokesman Farhan Haq said that the secretary-general encourages Iran to continue implementing all its nuclear commitments under the deal "as the participants continue to seek ways to overcome the considerable challenges the country faces."
The United Nations' nuclear watchdog, the International Atomic Energy (IAEA), said on July 8 that its inspectors verified "that Iran is enriching uranium above 3.67%," the limit allowed under the 2015 agreement.
Earlier on July 8, Iran called on European signatories of a landmark nuclear agreement to abstain from any rash move in response to Tehran's breaching the uranium-enrichment cap set by the 2015 deal.
If European parties to the agreement "do certain strange acts then we would skip all the next steps [in the plan to scale back commitments] and implement the last one," Foreign Ministry spokesman Abbas Musavi said, without specifying what that final step would be.
Musavi said he had no information on how far Iran had taken its enrichment, though a top aide to Supreme Leader Ayatollah Ali Khamenei previously suggested Iran had a need for 5 percent-enriched uranium.
Under the nuclear agreement, the cap for enrichment was set at 3.67 percent, a number closely monitored by the International Atomic Energy Agency (IAEA), the UN's nuclear watchdog.
Enriched uranium at the 3.67 percent level is enough for peaceful pursuits, and it is far below weapons-grade levels of 90 percent.
The IAEA said it was waiting for a report from its inspectors before commenting on Iran's move.
Asked if Tehran could withdraw entirely from the deal, Musavi said "all the options" were possible but "no decision has been made."
The remaining European partners of the international deal -- France, Germany, and Britain -- have urged Tehran to halt its advance towards breaching the cap.
But Tehran says it has lost patience with a perceived lack of action by the European side to help Tehran economically in the face of crippling U.S. sanctions reimposed following last year's withdrawal of the United States from the deal.
Oil Tanker Seizure
In Brussels, an EU spokeswoman said the bloc was "extremely concerned" by Iranian plans to breach the uranium-enrichment cap.
"We strongly urge Iran to stop and reverse all activities that are inconsistent with the commitments made under the JCPOA [nuclear agreement]," EU spokeswoman Maja Kocijancic told reporters on July 8.
Meanwhile, Iranian Foreign Minister Mohammad Zarif said the capture of an Iranian oil tanker by Britain amounts to "piracy" and has set "a dangerous precedent and must end now."
British Royal Marines seized the tanker on July 4 for trying to take oil to Syria in violation of European Union sanctions, an action that sparked Tehran’s anger and could escalate its confrontation with the West.
Gibraltar, which is a British protectorate, received permission from its Supreme Court to hold the tanker for 14 days. An Iranian Islamic Revolutionary Guards Corps commander threatened to seize a British ship in retaliation.
"Iran is neither a member of the EU nor subject to any European oil embargo. Last I checked, EU was against extraterritoriality. UK's unlawful seizure of a tanker with Iranian oil on behalf of #B_Team is piracy, pure and simple. It sets a dangerous precedent and must end now," Zarif tweeted.
Musavi also called the seizure by Britain of an Iranian supertanker off the coast of Gibraltar "piracy."
However, Musavi stopped short of suggesting Iran take actions against ships transiting through the Strait of Hormuz, the narrow mouth of the Persian Gulf through which 20 percent of the world's crude oil passes.
U.S. President Donald Trump warned Tehran on July 7 that "Iran better be careful." He didn't elaborate on what actions the U.S. might consider, but Trump told reporters: "Iran's doing a lot of bad things."