Now, the IRGC has reportedly seized a third ship, citing the same excuse that was eventually used to justify the seizure of the Riah. In that case, Tehran first claimed that naval forces had responded to a distress call after the commercial vessel experienced a malfunction. But after it became clear that no other country had received such a beacon, it was announced that the ship had supposedly been involved in the smuggling of Iranian oil. That claim remains dubious, as does the claim that the Impero had been traveling in the wrong direction as it entered the Strait of Hormuz. The ship’s operator insisted that it had been abiding by all relevant laws and regulations.

Similar doubts are now swirling around Tehran’s reference to smuggling as an explanation for the third IRGC seizure. The ship involved in that incident was not specifically identified in the state media reports, but it was purported to be taking the oil to neighboring country in the Gulf region. In reporting upon the incident on Sunday, the Associated Press did not expressly dispute Tehran’s claims but did note that “it was not immediately clear why a ship carrying Iranian fuel would transfer its cargo to energy-exporting Gulf States.”

Tehran’s official explanation for the latest seizure is arguably made marginally more credible by the fact that it was not explicitly contradicted by prominent figures within the regime or the IRGC. In the wake of the Impero incident, some such officials openly suggested that the British-flagged vessel had been targeted in retaliation for Britain’s seizure of the Grace 1 near Gibraltar. But even though this connection was not repeated on Sunday, all three incidents have been colored by the threats issued by current and former IRGC officers in the days after July 4, when the Grace 1 was stopped.

Those threats, in turn, were widely seen as part of an escalating campaign of force projection by the Islamic Republic. Even before directly seizing any commercial vessels, the IRGC was implicated in at least one of six acts of sabotage targeting tankers in the Gulf of Oman, which is adjoined to the Persian Gulf by the Strait of Hormuz. Footage was captured in June which showed an IRGC pulling alongside a damaged vessel and removing an object that was believed to be an unexploded limpet mine.

These weapons are known to have been used by Iran’s armed forces, and they were remnants of them were reportedly found on Kokuka Courageous and another tanker, the Front Altair that was damaged on the same day. Iranian mines were also suspected in the case of earlier explosions on four tankers that were anchored near the UAE in May.

And despite denying responsibility for all these incidents, the IRGC seized upon the abandonment of the Front Altair in order to take the crew into custody after demanding their release from another commercial vessel that had arrived on the scene to recover them first.

This presumably would have been the case with the crew of the Courageous, as well, had they not been recovered by the US Navy. And in fact, Iranian state media initially attempted to claim that the crews of both ships were taken to port in the Islamic Republic. It was not until the end of July that Iran finally released most of the crew of the MT Riah, although its captain and first mate remain in custody. The same appears to be true of all those who were detained along with the Impero. And Sunday’s state media reports indicated that Iran was also holding seven crew members from the most recent seizure.

Whether or not any of these detentions constitute direct retaliation for the Grace 1 incident or other instances of Western pressure, the Islamic Republic and the IRGC in particular seem to have committed themselves to asserting control over regional waterways in the midst of rising tensions with foreign adversaries. This position has been explicitly stated by several political and paramilitary officials, including Foreign Minister Javad Zarif, who came under US sanction last week after previously being excluded from a round of sanctions that focused on Supreme Leader Ali Khamenei and the IRGC.

In a televised news conference, Zarif underscored a change in posture by saying, “Iran used to forgo some maritime offences in … [the] Gulf but will never close [its] eyes anymore.” He also asserted Iran’s primary responsibility for “the security and safety of the Strait of Hormuz and the region.” This arguably constitutes a direct repudiation of US-led efforts to establish an international coalition with the defined goal of countering threats emanating from Tehran.

Zarif took aim at this plan, dubbed Operational Sentinel by the US State Department and the Pentagon, in his broader remarks on Monday. After decrying the prospective coalition as “hostile” and “provocative” last week, Zarif shifted the narrative toward boasting of its supposed failure. “Today, the United States is alone in the world and cannot create a coalition,” he said. “Countries that are its friends are too ashamed of being in a coalition with them.”

This claim apparently stems primarily from the recent news that the US had formally requested German participation in the coalition, only to be rejected. However, that rejection does not necessarily reflect German disinterest in constraining Iranian threats. In fact, German Foreign Minister Heiko Maas acknowledged the gravity of the situation but stated that his government would prefer a maritime security coalition to be led by the European Union rather than the US.

Notably, this was also the position of the UK government through late July. But now it has been reported that Britain will be a part of the US-led effort – a fact that raises questions about whether Berlin’s perspective on the situation might shift, as well. Meanwhile, France has neither committed to nor rejected either proposal, but Paris has traditionally taken a more assertive stance on issues of malign Iranian behavior, such as ballistic missile development, than its fellow European partners. Australia announced on Monday that it was seriously considering an American request for its participation in the Sentinel program.

In reporting on Britain’s emerging contribution to maritime security, Agence-France Presse drew a connection between that decision and the latest Iranian public gestures, including Zarif’s statement about US allies being “ashamed.” It may be that no specific incident sparked that decision, but British foreign policy has almost certainly been informed by an increasingly hardline turn in Iran’s dealing with competitors and adversaries. The same report acknowledged that it was unclear what other countries might participate in Sentinel; but there is little doubt that the US has regional support for an underlying strategy of “maximum pressure,” as tensions rise between Iran and Gulf States led by Saudi Arabia.

With all this in mind, Zarif’s gloating on Monday was surely premature. But it also reflects a growing alignment between supposedly moderate Iranian figures associated with President Hassan Rouhani on the one hand, and avowed hardliners like the IRGC on the other. The US Treasury’s recent imposition of sanctions on the Foreign Minister was explained in terms of his conveying hardline propaganda and acting as an apparent mouthpiece for the already-sanctioned supreme leader’s office.

Now that those sanctions are in place, Zarif has taken the lead in warning the European Union and the signatories of the 2015 Iran nuclear deal that Iranian nuclear facilities are preparing to initiate a third violation of the agreement. Speaking on this topic on Saturday, he did not specify what that new step would be, although Iranian officials have previously warned of plans to restart activity at the Arak heavy water plant, thereby generating plutonium which could be used in a nuclear weapon. Tehran has already announced violations of limits on stockpiles of nuclear material and allowed levels of uranium enrichment.

The clear purpose of these gestures is to put pressure on European governments for the sake of eliciting new concessions. In this sense, they fill a similar role as the tanker seizures, which threaten the security of international shipping in the hopes of securing the release of previously seized Iranian oil and, presumably, the subsequent non-enforcement of petroleum sanctions. Tehran has floated the idea of a direct exchange of the Stena Impero for the Grace 1, but the administration of newly elected British Prime Minister Boris Johnson has already rejected it.

Since then, Tehran has threatened legal action against the UK and has stepped up its rhetoric by accusing the British of helping the White House commit “economic terrorism.” But it is unlikely that there is any standing for the legal challenge, since the Grace 1 seizure was an instance of lawful enforcement of EU sanctions on trade with the Assad regime in Syria. Iran has offered no serious rebuttal to the British claim that that is where the oil was headed.

Pending the failure of that challenge, Iran may continue to exert control over the Persian Gulf, and it may feel emboldened in this by its partnership with stronger nations in the east. Last week, the head of Iran’s naval forces Hossein Khanzadi boasted of the signing of a new security agreement with Russia, which includes plans for joint military drills later this year. According to Khanzadi, aspects of the agreement are classified, “but overall, it is aimed at expanding military cooperation between the two countries.”

The extent of that prospective cooperation remains unclear, but Iran’s public claims about it underscore the likelihood of continued escalation in maritime tensions. However, much more information is needed before any conclusion can be drawn about whether Iran’s successful appeals to its existing allies are keeping pace with its alienation of Western powers that are wary of betraying the nuclear deal but also wary of accepting Iranian adventurism.