Iran's President Hassan Rouhani was quoted by the official IRNA news agency as calling the seizure "mean and wrong" during a Cabinet meeting. He warns London: "You are an initiator of insecurity and you will understand its repercussions", without elaborating.
Iran has demanded the immediate release of the oil tanker, while an Iranian Revolutionary Guards commander threatened last Friday to seize a British ship in retaliation.
Iran has now blown through several limits set under the deal - including uranium stockpile limits and enriching uranium to higher levels than permitted - and accused European leaders of failing to guarantee it the economic benefits it was promised.
Later that day, Iran's Foreign Ministry summoned Britain's ambassador to the country, Rob Macaire, to express its strong protest at the move.
Jackie Wolcott, the USA ambassador to worldwide organizations in Vienna, told a gathering of the global Atomic Energy Agency that Iran's recent moves to enrich uranium beyond the deal's limits amounted to "nuclear extortion".More news: Amazon is Also Developing a Lord of the Rings MMO
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The tanker had to be checked on by United Kingdom officials over the weekend as she stopped close to Iranian waters.
He also said Iran's increase in uranium enrichment was for peaceful aims, the semi-official news agency Tasnim reported. France and other countries have called on Iran to go back to complying with the nuclear deal. It has offered to return to the agreement, but Trump has long rejected the deal, saying it was too generous to Tehran and did not address its involvement in regional conflicts.
In May, the United States dispatched a carrier group, bombers and fighter jets to the Persian Gulf region in response to alleged Iranian threats.
He also said Iran's downing of the USA drone is a testament to its growing military power. AbbasAraqchi said Iran was continuously in touch with the British government and is now pursuing legal channels on the seizure.
The Gibraltar Government said the vessel's detention related to the suspected destination of the cargo, Syria's Banyas refinery, which is owned by the Banyas Oil Refinery Company and subject to European Union sanctions.