The Treasury Department's Office of Foreign Assets Control issued a warning to shippers on Friday that fulfilling any demand for an Iranian toll in exchange for passage through the Strait of Hormuz risks exposure to U.S. sanctions.

"OFAC is issuing this alert to warn U.S. and non-U.S. persons about the sanctions risks of making these payments to, or soliciting guarantees from, the Iranian regime for safe passage. These risks exist regardless of payment method," its alert said.

Demands to pay a toll could come in a variety of ways, including "fiat currency, digital assets, offsets, informal swaps, or other in-kind payments," such as charitable donations to the Iranian Red Crescent Society, the alert said.

The OFAC also reiterated that the U.S. naval blockade of Iranian ports remains in effect.

The alert comes as shipping traffic through the critical shipping channel remains at a virtual standstill and the indefinite ceasefire between the U.S. and Iran drags on without a clear resolution to the war -- or a full reopening of the strait -- in sight.

-ABC News' Nicholas Kerr

President Donald Trump has sent letters alerting Congress that he "will continue to direct United States Armed Forces consistent with my responsibilities and pursuant to my constitutional authority to conduct United States foreign relations and as Commander in Chief and Chief Executive."

Despite facing the 60-day deadline under the War Powers Act, the president is not asking Congress for authorization, rather providing an update to the posture of U.S. forces in the region.

Echoing Defense Secretary Peter Hegseth, the president noted that he ordered a two-week ceasefire on April 7 that has since been extended.

"On April 7, 2026, I ordered a 2-week ceasefire. The ceasefire has since been extended," Trump wrote. "There has been no exchange of fire between United States Forces and Iran since April 7, 2026. The hostilities that began on February 28, 2026, have terminated."

Trump also stressed that he ordered Operation Epic Fury "consistent with my responsibility to protect Americans and United States interests at home and abroad, and in furtherance of United States national security and foreign policy interests."

So far, 45 commercial vessels have been directed to turn around or return to port as part of the U.S. naval blockade of Iranian ports, U.S. Central Command said Friday.

President Donald Trump said Friday that he is "not happy" after recent talks with Iran.

"We just had a conversation with Iran. Let's see what happens. But I would say that I am not happy," Trump told reporters before departing the White House.

Trump said the Iranian leadership is "very disjointed" and "argumentative with each other."

"They come back -- one says one thing, one says another. They're very confused," he said, adding that he's "not satisfied" with what's been offered.