narak and Chahbahar in Sistan and Baluchistan province, IRNA reported.

As the strikes began, a vessel caught fire early Monday in the Strait of Hormuz after being hit by a projectile near the coastline of Oman, the British military's United Kingdom Maritime Trade Operations center said. The crew abandoned the vessel, which was adrift and still ablaze hours later, the UKMTO said.

The route around Oman has been the one the U.S. military has encouraged ships to travel to avoid Iran's control. The Guard later claimed it was targeting tankers in the strait.

Tehran has retaliated by hitting U.S.-allied countries throughout the Middle East. Bahrain sounded its missile alert sirens Monday morning, while Kuwait said its air defense were firing at an incoming Iranian barrage.

The Strait of Hormuz remains key to the conflict

Trump has threatened to target Iran's power stations and bridges to try to compel Tehran to loosen its hold on the Strait of Hormuz, which saw one-fifth of traded global oil supplies transit before the war. Recent attacks suggest the U.S. military is carrying out that plan.

The U.S. in the past week reimposed a naval blockade on Iranian ports to halt its shipments of crude oil. The military on Saturday said it had redirected six ships and disabled one since then.

The halfway point has passed in the 60 days the deal set out to negotiate the permanent end of the war and other issues, including Iran's nuclear program.

U.S. Secretary of State Marco Rubio told reporters that the U.S. is still open to negotiating with Iran but that  it has to be real. 

 We're going to continue to respond. If the door opens to diplomacy - if the guys that want to do something productive for Iran win and take control of that system, or take control of the negotiations - that'll be a very positive development,  Rubio said.  That's not where we are tonight, unfortunately. 

Iranian Foreign Ministry spokesperson Esmail Baghaei hours later acknowledged that  proposals conveyed through mediators have been communicated to us,  but he declined to elaborate on their substance.

Mohammad Javad Zarif, a former Iranian foreign minister who helped elect the country's reformist President Masoud Pezeshkian, acknowledged in an essay published Monday by Foreign Policy that the interim  deal could never survive such dissonance  over the Strait of Hormuz.

 As the current conflict makes clear, Washington cannot eliminate the Iranian government,  Zarif wrote.  Only diplomacy, a new peace agreement, and a new security framework produced by regional states and for regional states will allow the United States to turn its attention elsewhere. 

However, Zarif did warn the country's theocracy that  if Iran repeatedly threatens maritime traffic, it could turn much of the world against it. 

Iranian authorities on Sunday said at least 50 people have been killed and 517 wounded in the latest rounds of U.S. strikes. Since the war began on Feb. 28, 17 U.S. service members have been killed.

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Associated Press writers Nasser Karimi in Tehran, Iran, and Michelle L. Price in Washington contributed to this report.