The most significant in a series of events involving Iran during the week occurred July 19 with an announcement from the Revolutionary Guards Corps that it had seized a British tanker — and briefly halted the progress of another — in the Arabian Gulf. The tankers capture adds yet another layer of stress atop already tense relations between Iran and the United States and its allies, said the Stratfor intelligence platform. Several previous incidents either involving or aimed at Iranian interests earlier this week have added to the air of tension surrounding the US-Iranian standoff. Before news of the tanker seizure broke, a fire ripped through a facility in Iraq storing ballistic missiles that Iran provided to Iraqi militias aligned with Tehran — possibly as a result of an airstrike by unknown assailants. And on July 13, the IRGC detained a tanker in the Gulf that it said was involved in a fuel-smuggling operation. Amid the escalation, the US Navy claimed on July 18 it had destroyed an Iranian drone that had been menacing one of its ships.Possible act of retaliation Late in the day on July 19, a large British-flagged tanker, the Stena Impero, made a sudden and unplanned turn toward Iran. The vessel was tracked sailing toward Iranian ports near Bandar Abbas before its transponder quit transmitting. A second tanker, the British-owned and Liberian-flagged Mesdar followed a similar course before its transponder was shut off. The IRGC subsequently said, however, that it had briefly halted the Mesdar to caution it about "environmental regulations" and other matters before permitting it to proceed. The incidents prompted British officials to convene an emergency ministerial meeting. The Iranian actions are likely being construed as a retaliatory measure for the United Kingdoms July 4 detention of the Iranian tanker Grace 1, which British authorities are holding in Gibraltar on suspicion of smuggling Iranian oil to Syria. If so, Iran is likely to hold the Stena Impero as a bargaining chip to convince the United Kingdom to release the Grace 1. Every such hostile incident, however, elevates the risk that a wider conflict will emerge between Iran and its adversaries. And the possibility of new British sanctions on Iran over these incidents could lead Iran to engage in even more provocations, increasing the chances that the United States and its allies will respond with a limited military strike targeting Iranian assets.A tanker no one claims The United States was first to suggest that Iran may have detained a tanker whose transponder had gone silent on July 13 as it entered Iranian waters in the Strait of Hormuz. The MT Riah, a small oil products tanker with a capacity of just 2 million liters (about 12,500 barrels), was initially identified as Panamanian-flagged and Emirati-owned. However, the United Arab Emirates disavowed ownership and said no Emiratis had been detained. The initial events resembled those of previous incidents in the region over the last two months in which Iran or Iranian-linked militias targeted six oil tankers in two separate incidents. The US State Departments response to Iran on July 18 — a demand for an immediate release of the MT Riah — suggests that Washington is viewing the incident as yet another Iranian provocation. The US characterization of the event, however, was blunted somewhat by a later IRGC claim that it had detained the tanker and arrested the crew on for allegedly smuggling fuel. That explanation has the ring of plausibility, given Irans long campaign to rein in smuggling operations in which fuel subsidized in Iran is sold abroad for higher prices. In fact, in April, the IRGC seized a small tanker bearing 11 million liters of fuel smuggled out of Iran in the Strait of Hormuz. However, given the seizure of the Stena Impero on July 19, Iran might have seized the Panamanian-flagged MT Riah on the mistaken belief that it was British-owned, which could account for why Iran’s story is unclear at this point. The MT Riah certainly exhibits the hallmarks of a vessel used in smuggling operations. Over the past year, it has turned off its transponder more than two dozen times, making no port calls while conducting dozens of ship-to-ship transfers. The IRGC, of course, is itself involved in lucrative oil smuggling operations, meaning that the detention of the MT Riah could represent an effort by the IRGC to undermine a competing smuggling ring. Nonetheless, since the news broke, no entity has either claimed ownership of the MT Riah or revealed the nationalities of the crew members in custody. An airstrike no one claims Meanwhile in Iraq, video footage of a fire in a warehouse facility housing Iranian-supplied ballistic missiles early on July 19 points to the possibility of an attack. The Pentagon, however, has so far denied involvement in any airstrike. Nevertheless, US involvement remains plausible. The reported deaths of two Lebanese Hezbollah members in the July 19 incident could also point to possible Israeli involvement in the attack, given the countrys concerns about growing stockpiles of Iranian weapons in Shiite militia warehouses in Iraq. If Israel was involved in the warehouse explosion, it would mark a notable escalation toward Israeli efforts to challenge Iran militarily. This week, the United States also enacted sanctions under the Global Magnitsky Act to push against Iran’s reach into Iraq by restricting the ability of two leaders of Iranian-allied militias to travel or conduct financial transactions. The leaders of the 30th and 50th Brigades of the Popular Mobilization Units — Waad Qado and Rayan al Kildani — were sanctioned along with two former provincial governors, one of whom is known to have close ties with Iran. The sanctions highlight the multifaceted nature of US efforts to curtail Iranian influence across the Middle East. And despite Washingtons denial, if the United States was involved in the warehouse explosion, it would be a logical effort to send a message to Iran that using Iraq as a staging ground to attack US forces, assets and allies will not be tolerated.