The White House says Tehran is supplying a Yemeni rebel group with weapons and tactical intelligence.
The United States has accused Iran of being deeply involved in attacks by Houthi rebels on commercial ships in the Red Sea.
Tehran's support for the Yemeni rebel group includes weapons and tactical intelligence, the White House said on Friday, as it presented newly declassified intelligence that it claims shows Iran's involvement in the attacks.
“We know that Iran has been heavily involved in planning operations against commercial ships in the Red Sea,” White House national security spokeswoman Adrienne Watson said in a statement.
He added, “This is consistent with Iran's long-term material support and encouragement of the Houthis' destabilizing actions in the region.”
“This is an international challenge that requires collective action,” Watson said.
The White House said visual analysis showed nearly identical traits between Iranian KAS-04 drones and unmanned vehicles used by the Houthis, as well as consistent traits between Iranian and Houthi missiles.
Al Jazeera was unable to independently verify the White House allegations.
The Houthis, who control large parts of Yemen including the capital, Sanaa, launched dozens of drone and missile attacks on commercial ships in the Red Sea in what the group described as a show of support for Palestinians facing Israeli bombing in Gaza.
The attacks have effectively rerouted much of global trade by forcing shipping companies to sail around Africa, driving up costs and delaying deliveries of shipments of energy, food and consumer goods.
More than a dozen shipping companies, including the Italian-Swiss giant Mediterranean Shipping Company, the French CMA CGM, and the Danish AP Moller-Maersk, have halted transit through the Red Sea due to the attacks.
Washington announced earlier this week the launch of a multinational force that includes more than 20 countries to protect ships crossing the Red Sea.
Last week, a US destroyer equipped with guided missiles shot down 14 attack drones believed to have been launched from Houthi-controlled areas in Yemen.
The Houthi leadership warned that it would respond to “American battleships” and “American interests” if it was attacked.
Tehran said it supports the Houthis politically, but denies sending weapons to the group.
Iran's Foreign Ministry last month rejected Israeli accusations that the Houthis were acting under its direction when they seized an Israeli-owned ship and denied responsibility for a drone shot down by a US guided-missile destroyer.
The Houthis, who have effectively maintained a UN-brokered truce with the Saudi-backed government since last year, rose up against the Yemeni government in 2014, sparking a devastating civil war.
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