DUBAI, United Arab Emirates (AP) — The Iran war risked reigniting after the U.S. tried to force open the Strait of Hormuz for commercial shipping, though a ceasefire seemed to be holding Tuesday even after the United Arab Emirates said Iran fired missiles and drones at it.

Iran’s powerful parliamentary speaker and chief negotiator, Mohammad Bagher Qalibaf, accused the U.S. of undermining regional security with the effort to end Iran’s stranglehold on the strait and warned that Tehran will respond.

The U.S. military said two American-flagged merchant ships successfully transited the strait on Monday, the first day of the effort, and that it fired on Iranian forces, sinking six small boats that were targeting vessels.

Disputing Washington’s claim of sinking six boats, an Iranian military commander said two small civilian cargo boats were hit on Monday, killing five civilians, Iran’s state TV reported.

Ship tracking data showed a Panamanian-flagged crude oil tanker heading toward the center of the strait Tuesday morning after leaving an anchorage in the Persian Gulf, though it was unclear if it would try to pass through. The tanker had a stated destination of Singapore, according to the MarineTraffic ship tracking site.

Iran’s effective closure of the strait, through which about a fifth of the world’s trade in oil and natural gas typically passes, along with fertilizer and other petroleum-derived products, has sent fuel prices skyrocketing, rattled the global economy and proved a major strategic advantage in negotiations to end the war. Breaking that grip would deny Tehran a major source of leverage.

But such efforts risk reigniting the full-scale fighting that erupted when the U.S. and Israel attacked Iran on Feb. 28, prompting it to close the strait.

Iran accuses US of ceasefire violation

Iran has called the new U.S. effort a violation of the fragile ceasefire that has held for more than three weeks.

In a post on X on Tuesday, Qalibaf accused Washington of undermining shipping security in the Strait of Hormuz, and warned that a “new equation” there is taking shape.

Source: WPLG