The U.S. and Iran exchanged fire in the Strait of Hormuz on Thursday, a U.S. official confirmed to Axios.

Iranian state media reported that three U.S. destroyers were targeted by the Iranian navy, while the U.S. official said the U.S. conducted strikes on targets in the strait.

The big picture: The U.S. official said the exchange did not constitute a resumption of the war, but the Iranian military described the U.S. strikes as a ceasefire violation and threatened retaliation. The extent of the strikes and resulting damage are unclear at this time. Iran’s military said the U.S. had targeted an oil tanker and another ship entering the strait.

President Trump pulled back on his operation for the Navy to facilitate shipping through the strait on Tuesday but left the U.S. blockade in place.

The confrontation appears to have come as the U.S. attempted to enforce the blockade.

Catch up quick: Iran responded to the since-abandoned U.S. operation on Monday by firing on U.S. naval vessels, commercial ships, and the United Arab Emirates.

Trump’s pullback came as the U.S. and Iran negotiate on a one-page memo to end hostilities and lay the groundwork for more detailed negotiations.