The United States and six other countries imposed sanctions on Wednesday on 25 corporations, banks and people linked to Iran's support for militant networks including Hezbollah, the U.S. Treasury Department said in a statement.
The targets were announced by the Terrorist Financing Targeting Center (TFTC) nations - which also include Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates - as Treasury Secretary Steve Mnuchin was on a Middle East trip to finalize details of an economic development plan for the Palestinians, Jordan, Egypt and Lebanon.
All 25 targets were previously sanctioned by the United States.
"The TFTC's action coincides with my trip to the Middle East, where I am meeting with my counterparts across the region to bolster the fight against terrorist financing," Mnuchin said in the Treasury statement.
In Jerusalem on Monday, Mnuchin said the United States would increase economic pressure on Iran over its nuclear program, making the pledge during a Middle East trip that includes visits to U.S. allies Israel and Saudi Arabia.
Sanctions reimposed on Tehran by President Donald Trump after he withdrew the United States from world powers' 2015 nuclear pact with Tehran have dried up Iranian oil revenues and cut Iranian banks' ties to the financial world.
Twenty-one of the targets announced Wednesday comprised a vast network of businesses providing financial support to the Basij Resistance Force which is part of the Revolutionary Guards Force, the Treasury said.
It said shell companies and other measures were used to mask Basij ownership and control over multibillion-dollar business interests in Iran's automotive, mining, metals, and banking industries, many of which have operate across the Middle East and Europe.
The four individuals targeted were Hezbollah-affiliated and help coordinate the group's operations in Iraq, it said.