The US Treasury Department has issued sanctions against four Iranian officials on the same day that Tehran’s navy seized a US-chartered tanker.

There is no clear link between the two incidents, as the department’s Office of Foreign Assets Control (Ofac) made no mention of the tanker seizure in the new sanctions.

But the incident adds to tit-for-tat blows between Washington and Tehran, with some seeing Iran’s seizure of the 159,000-dwt Advantage Sweet (built 2012) as a response to US crude seizures.

The Treasury Department did not immediately respond to a question from TradeWinds about whether the move had any link to the tanker seizure.

Ofac’s sanctions targeted four members of Iran’s Islamic Revolutionary Guard Corps’ intelligence arm, citing the wrongful detention of US nationals in Iran. Revolutionary Guard counterintelligence official Ruhollah Bazghandi, commander Mohammad Kazemi, intelligence organisation co-deputy chief Mohamad Mehdi Sayyari and co-deputy chief and brigadier general Mohammad Hasan Mohagheghi were added to the US blacklist.

The agency said the corps’ intelligence arm frequently holds and interrogates detainees in Evin Prison and has had a direct role in repression against protesters and arrests of dissidents, some of whom are dual citizens with US passports.

The sanctions were the first under an executive order signed in July by US President Joe Biden aimed at bringing “hostages and detained US national home”.

Ofac also took similar actions against Russia’s Federal Security Service, also for detentions of US nationals.

“Today’s action targets senior officials and security services in Iran and Russia that are responsible for the hostage-taking or wrongful detention of US nationals abroad,” said Treasury undersecretary Brian Nelson.

“We are committed to bringing home wrongfully detained US nationals and acting against foreign threats to the safety of US nationals abroad.”

As TradeWinds reported earlier in the day, Advantage Tankers’ Advantage Sweet was boarded by Iranian forces on Thursday while the vessel was on charter to California energy giant Chevron.

The US Navy at first blamed naval forces of Iran’s Revolutionary Guard, which it said was consistent with prior events.

“However, after sending a P-8 Poseidon maritime patrol aircraft to monitor the situation, we have since been able to determine the IRIN (Iranian navy) conducted the seizure,” the US Navy’s Fifth Fleet said on Twitter.

As of this writing, satellite tracking services have not seen a signal from the Marshall Islands-flag suezmax tanker’s AIS transponder for 10 hours. TradeWinds’ calls to the vessel rang unanswered.

The Marshall Islands is in contact with the owner and operator of the Advantage Sweet but cannot provide more information at this time, said International Registries spokeswoman Laura Sherman, whose US company manages the country’s registries.

TankerTrackers said on Twitter that the vessel was bound for the US at the time of its boarding.

“We expect to locate her shortly in the anchorage of Bandar Abbas, where she and her Kuwaiti oil cargo will be held hostage for months,” the tracking service said.