Latest warning comes as Iranian state media reports Tehran has presented new peace proposal to US.

The United States has warned that any shippers paying tolls or other fees to Iran for passage through the Strait of Hormuz risk being sanctioned.

The warning on Friday comes as a US naval blockade of the strait continued for its third week, amid stalled US-Iran ceasefire talks. Iranian President Masoud Pezeshkian has called the ongoing siege on the country’s ports “intolerable”.

Iran’s influence over, and ability to effectively close, the Strait of Hormuz emerged as a key point of leverage shortly after the US and Israel began launching attacks on Iran on February 28.

About one-fifth of the global crude oil and liquefied natural gas maritime shipments pass through the arterial waterway.

In its past proposals to end the war, Iran has proposed charging fees or tolls for vessels seeking to pass through the state. Washington has repeatedly rejected the prospect.

The advisory from the Department of the Treasury’s Office of Foreign Assets Control said Iran may offer shippers fiat currency, digital assets, offsets, informal swaps, or other in-kind payments.

It said those also included payments framed as charitable donations, including to the Iranian Red Crescent Society, Bonyad Mostazafan, or Iranian embassy accounts.

“OFAC is issuing ‌this alert to warn US and non-US persons about the sanctions risks of making these payments to, or soliciting ‌guarantees ‌from, the Iranian regime for safe passage,” it said.

“These risks exist regardless of payment method,” it said.

Both the government of Iran and the International Revolutionary Guard Corps (IRGC) remain under US sanctions.

The advisory on Friday came as Iranian state media reported that Tehran had sent a new proposal for a lasting ceasefire to the Trump administration.

A White House spokesperson said it does not “detail private diplomatic conversations”, declining to confirm receipt of the proposal.

The spokesperson, Anna Kelly, added that “Trump has been clear that Iran can never possess a nuclear weapon, and negotiations continue to ensure the short- and long-term national security of the United States”.

Both sides have largely halted attacks since reaching a tentative agreement to pause fighting on April 7. Trump has repeatedly threatened to resume attacks amid the stalled negotiations.

Iran’s Foreign Minister Abbas Araghchi said Friday that Tehran remains open to diplomacy with the US if Washington alters its “expansionist approach” and “threatening rhetoric”.