Iran on July 8 called on European signatories of the 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.
On July 7, Iran said it was hours away from breaching the uranium-enrichment limit, stepping back from another commitment more than a year after the United States pulled out of the nuclear accord.
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%-enriched uranium.
Under the nuclear agreement, the cap for enrichment was set at 3.67%, a number closely monitored by the International Atomic Energy Agency (IAEA), the UN's nuclear watchdog.
Enriched uranium at the 3.67% level is enough for peaceful pursuits, and it is far below weapons-grade levels of 90%.
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 US sanctions.
Separately, Behrouz Kamalvandi, a spokesman for Iran's nuclear agency, said in a state television interview on July 8 that Tehran might consider going to 20% enrichment or higher as its third step if the material is needed.
Enriching uranium at 20% is a short technical step away from reaching levels of 90%.
Musavi also called Britain's seizure of an Iranian supertanker off the coast of Gibraltar "piracy."
However, he stopped short of suggesting Iran take actions against ships transiting through the Strait of Hormuz, the narrow mouth of the Arabian Gulf through which 20% of the world's crude oil passes.
Iran's Defense Minister Amir Hatami has said Britain's detention last week of an Iranian tanker was a threatening and incorrect action.
Hatami made the statement in a speech broadcast live on state television on July 8.
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, its government said on July 5, the day an Iranian Revolutionary Guards Corps commander threatened to seize a British ship in retaliation.
Hatami also said Iran's downing of an American drone last month sent a message that Tehran would defend its borders.
US President Donald Trump warned Tehran on July 7 that "Iran better be careful." He didn't elaborate on what actions the US might consider, but Trump told reporters: "Iran's doing a lot of bad things."