Washington(CNN) The Biden administration on Friday sanctioned the commander of the military drone unit of Iran's Islamic Revolutionary Guard Corps (IRGC) under whose leadership the US says Iran conducted a deadly attack on a shipping vessel earlier this year.
The US also sanctioned a number of other individuals and companies connected to Iran's Unmanned Aerial Vehicle (UAV) program.
The sanctions come three months after the drone attack on the Mercer Street vessel, which was off the coast of Oman at the time -- an assault that ratcheted up tensions in the region, prompted unified outcry from the G7 coalition of nations, and vows from the US of a coordinated response.
The announcement of new sanctions also comes a week after a drone attack on a US base in Syria that a US official attributed to Iran and days after the hardliner Raisi government in Iran said it would return to negotiations over the Iran nuclear deal after months of delay.
According to the US Treasury Department, Brigadier General Saeed Aghajani oversees the IRGC's Aerospace Force Unmanned Aerial Vehicle (UAV) Command and "directs the planning, equipment, and training" for its operations.
"Under his leadership," the Treasury Department said Friday, the UAV Command orchestrated the attack on the Mercer Street at the end of July that left two crew members dead.
The Treasury Department said in press release that "Aghajani also was behind a UAV attack against a Saudi Arabian oil refinery in 2019."
"Iran's proliferation of UAVs across the region threatens international peace and stability. Iran and its proxy militants have used UAVs to attack US forces, our partners, and international shipping," Deputy Secretary of the Treasury Wally Adeyemo said in a statement.
Iran condemned the new sanctions on Friday, according to state news agency IRNA.
"Imposing the new sanctions is a sign of the White House's contradictory behavior," Foreign Ministry spokesperson Saeed Khatibzadeh said, calling it "Ironic" that the US government is "claiming to have the intention to come back to JCPOA [nuclear agreement], but is now following the suit of Trump in continuing the sanctions, and is sending the message that is not trustable."
A US Defense Department expert team concluded in August that the drone behind the deadly Mercer Street attack was produced in Iran.
The investigative team found that the tanker was targeted by three explosive UAVs, one of which was successful in causing "extensive damage" to the ship and required "calculated and deliberate retargeting of M/T MERCER STREET by Iran," according to Central Command.
"The use of Iranian designed and produced one way attack 'kamikaze' UAVs is a growing trend in the region," US Central Command said. "They are actively used by Iran and their proxies against coalition forces in the region, to include targets in Saudi Arabia and Iraq."
The US team shared evidence with both British and Israeli explosive experts, according to the statement, and "both partners concurred with the US findings."
Iran denied involvement in the attack, which was jointly condemned by the G7 coalition of nations.
The foreign ministers of those nations -- Canada, France, Germany, Italy, Japan, the United Kingdom and the United States of America and the High Representative of the European Union -- called it "a deliberate and targeted attack, and a clear violation of international law."
"All available evidence clearly points to Iran. There is no justification for this attack," they said in a joint statement in early August, a day after hardliner Ebrahim Raisi was sworn in as President of Iran.