The limpet mine explanation was substantiated within a day of the blasts by surveillance drone footage which seemed to show an unexploded mine being removed from the hull of the Kokuka Courageous by the Islamic Revolutionary Guard Corps. The grainy footage was followed by higher resolution still images apparently depicting the same incident, which the US explained as an effort by Iranian operatives to conceal evidence of the regime’s involvement. That effort was evidently not successful, as American investigators managed to gather physical evidence from the ships anyway.

US Navy officials spoke about the investigation on Wednesday and stated that the remnants of a limpet mine had been recovered from one of the target ships. This mine was said to bear a “striking resemblance” to limpet mines known to have been used by the Islamic Republic in the past. Commander Sean Kido of the Navy’s Fifth Fleet added that this discovery further undermined any alternative explanation for the explosions, particularly those involving flying objects.

This evidence will no doubt encourage American officials to continue pressing for a more broadly coordinated international response to threats stemming from the Iranian regime. Those threats have been at the forefront of US foreign policy for the past several weeks, ever since intelligence data in May led to National Security Advisor John Bolton announcing the accelerated deployment of a US aircraft carrier group to the waters of the Middle East.

The intelligence in question reportedly included satellite images showing the increased presence of missiles on Iranian boats in the Persian Gulf, plus comments from IRGC officials suggesting that regional proxies should be prepared for open conflict with US assets and allies. The aircraft carrier deployment was accompanied by the deployment of a B-52 bomber task force, which was in turn followed by the announcement that 900 additional support troops would be stationed in the region, joining 600 whose deployments were to be extended.

The new troop deployment was more than doubled this week in an apparent response to the tanker attacks, as tensions between Iran and the US continued to escalate. In the midst of that escalation, US President Donald Trump has offered assurances that his administration is not on the path to war. He has also expressed confidence in recent days that military deterrence measures are convincing the Iranian regime to recalculate its activities.

However, Iranian Supreme Leader Ali Khamenei has maintained a defiant tone, and in a meeting with Japanese Prime Minister Shinzo Abe that coincided with last week’s tanker attacks, he reportedly rebuffed a message from the US president. Trump has maintained a policy of exerting maximum pressure on the Islamic Republic while also leaving the door open to unconditional talks. But Iranian officials have generally rejected that prospect and have sought to give the impression that they are unmoved by either economic or military pressure.

Toward that end, the state news outlet IRNA issued a report on Wednesday claiming that the IRGC had shot down an American drone after it passed into Iranian territory. When asked about this claim, US Central Command spokesman Bill Urban declined to comment directly but stated that “there was no drone over Iranian territory.”

Regardless of the truth of the IRNA report, it appears tailor-made to feed a longstanding narrative about Iranian readiness for conflict with the world’s leading superpower. Of course such claims are not taken seriously by military experts, and President Trump even worked to downplay the seriousness of the Iranian threat this week by describing the tanker attacks as “very minor.” This did not, however, undermine his administration’s efforts to convince the international community both of Tehran’s culpability for the specific attacks and of its more general penchant for unprovoked violence.

The IRNA report is part of a pattern of military rhetoric in state media, which may ultimately strengthen the Trump administration’s case. And that claim stood alongside a vaguer but no less proud claim made on Tuesday by the Iranian Ministry of Intelligence, regarding “a heavy blow against America’s international spy network.” CNN noted that this was similar to another, similarly unsubstantiated statement published by Mehr News Agency in April.

The US dismissed the notion that the Ministry of Intelligence was “preventing American plans from succeeding.” But it was not clear what plans, if any, had motivated this statement. The Ministry may have been referring, at least in part, to competing narratives over regional threats and Iran’s role. But if so, it remains to be seen what effect the US may still have on its Middle Eastern and European allies. At the same time, it remains to be seen whether American warning start to appear more credible as Iran continues to respond to the current tensions with boastful rhetoric.