"A Tanker For A Tanker" read the main headline of the ultra-hard-line Iranian daily Kayhan on July 20, a day after Iran's Islamic Revolutionary Guards Corps (IRGC) seized a British-flagged tanker, the Stena Impero, and its 23-member crew in the Persian Gulf.
The IRGC accused the tanker of violating international maritime laws and regulations and of causing pollution in the Strait of Hormuz.
Later, an Iranian official claimed the tanker was seized after a collision with an Iranian tanker.
Meanwhile, speaking on July 22, a spokesman for Iran's government called the seizure a "legal measure."
"Seizing the British tanker was a legal measure by Iran. Iran confronted the ship [to ensure] the region's security," Ali Rabiei told reporters in Tehran.
Whatever the motivation, the move is being widely seen -- plain and simple -- as retaliation for the seizure of an Iranian tanker on July 4 off the coast of Gibraltar over suspicions it was transporting oil to Syria in violation of EU sanctions.
It is part of Iran's wider response, analysts say, to Washington's campaign of "maximum pressure," which has crippled the country's economy and put the country under enormous strain.
Dina Esfandiary, a fellow at The Century Foundation think tank in New York, says Iran is trying to up the ante in the crisis with the United States "by responding individually to each move the U.S. and its allies make, but doing so in a relatively calibrated manner that makes it difficult for the other side to simply resort to war."
"Seizing the British tanker was a simple way of making good on its threats after the Brits seized a tanker with Iranian oil reportedly bound for Syria two weeks ago," she says. "It is important for the Revolutionary Guards to be seen as being credible when making threats in the current tit-for-tat spats."
Ali Fathollah-Nejad, a visiting fellow at the Brookings Doha Center of the Washington-based Brookings Institution think tank, says Iran -- at least initially -- thought it could swap the British tanker with its own seized supertanker, the Grace 1.
However, he says that any such exchange may be difficult to pull off, considering both the legal and political issues involved.
"This leaves all parties concerned in a situation of stalemate," Fathollah-Nejad told RFE/RL.
A video released by the IRGC and published by Iran's state-controlled media showed men in military fatigues wearing blacks ski masks descending on the Stena Impero from a helicopter, while shouts of "Allahu Akbar" could be heard in the background.
Speedboats were seen pulling alongside the tanker, amid reports that the IRGC had employed similar tactics to those used by British Royal Marines to capture the Grace 1 earlier this month.
The IRGC has raised the Iranian flag on the British-flagged tanker, according to photos published by Iranian news agencies.
A video shared online also suggests that the Islamic call to prayer is being played on the tanker, while a selfie taken by an IRGC member aboard the captured vessel made the rounds among Iranian hard-liners, who have praised the move.
In a post on Twitter on July 22, government spokesman Rabiei insisted that the seizure of the Stena Impero was not a retaliatory move, while accusing Britain of undermining good faith in bilateral relations.
"We hope Britain would attempt to restore the #trust, " he said.
Iran has in past weeks attempted to push back against Washington's pressure through a series of calibrated steps, including by enriching uranium above the limits set by the 2015 nuclear deal, which the United States exited last year while reimposing tough economic sanctions.
Tehran has been trying to raise pressure on the European parties to the nuclear deal to help it bypass U.S. sanctions and benefit economically from the accord, under which Iran agreed to limit sensitive nuclear work in exchange for sanctions relief.
Iran appears to also be trying to gain leverage for possible talks with the United States, even though the country's leaders have insisted that talks will only be possible if sanctions are lifted.
Iran has said repeatedly it is not after war with the United States and its allies. But analysts warn that Tehran's strategy could backfire by raising the risks of miscalculations that could lead to a conflict in the Persian Gulf.
"Given that there are no channels of de-escalation, this kind of tit-for-tat move could easily end up in a downward spiral leading to military confrontation," Esfandiary warns.
Britain is due to announce on July 22 a package of diplomatic and economic measures, including possible asset freezes in response to the capture of the tanker, The Daily Telegraph reported over the weekend.
British Prime Minister Theresa May convened an emergency meeting of ministers and security officials on July 22 to discuss possible measures.
EU countries have condemned Iran's actions, with France and Germany calling on Iran to return the British-flagged tanker and its crew.
British Foreign Secretary Jeremy Hunt warned over the weekend that Iran appears to have chosen a "dangerous path of illegal and destabilizing behavior" by seizing the British tanker.