The United States on Tuesday expanded its sanctions targeting Iran’s oil sector, taking further aim at the network of petroleum shipping magnate Mohammad Hossein Shamkhani, the Treasury Department said, according to Reuters.

Treasury Secretary Scott Bessent said the department had also frozen $130 million held in digital wallets linked to Iran’s central bank, hitting a sector that has seen increased activity since the start of the war.

The move came after US forces carried out a fourth straight day of strikes against Iran and reimposed a naval blockade, with Iran in turn hitting ships in the Strait of Hormuz, according to the International Maritime Organization.