They also came as Iranian officials have said Washington and Tehran are debating a one-page U.S. proposal for the sides to reopen the strait and cease hostilities for 30 days as they negotiate a comprehensive deal to end the war.

Secretary of State Marco Rubio, asked about the state of negotiations, said that the United States expected a “response” from Iran on Friday. And despite the exchanges of fire in recent days, both President Trump and Iran’s foreign ministry have insisted that their monthlong cease-fire was holding.

U.S. Central Command said on Thursday that “unprovoked Iranian attacks” on three American destroyers had involved missiles, drones and small boats. In response, the U.S. military said it had “targeted Iranian military facilities responsible for attacking U.S. forces,” including missile and drone launch sites.

The Iranian military said the United States had violated the cease-fire a day earlier by firing on an Iranian oil tanker trying to cross an American blockade. It said it had “retaliated by attacking U.S. military vessels.”

Mr. Trump, speaking to reporters in Washington on Thursday evening, dismissed the Iranian attacks as a “trifle” and again warned that Iran “better sign their agreement fast,” an apparent reference to the one-page U.S. proposal. A key hurdle was the U.S. demand for advance commitments on the fate of Iran’s nuclear program and its stockpile of highly enriched uranium, three senior Iranian officials said.

On Friday, the Iranian foreign minister, Abbas Araghchi, questioned in a social media post whether the U.S. strikes were a “crude pressure tactic.” He added: “Every time a diplomatic solution is on the table, the U.S. opts for a reckless military adventure.”

Here’s what else we’re covering:

• United Arab Emirates: The U.A.E.’s defense ministry said on Friday that its air defense systems had intercepted missiles and drones from Iran, a day after Iranian officials blamed the Emirates for reported strikes in southern Iran.

• Markets: Oil prices climbed, then slid, and global stocks fell on Friday after the U.S. said it had attacked Iranian military sites. Read more ›

• Lebanon: Fighting intensified on Friday between Israel and Hezbollah, the Iran-backed Lebanese militant group, fraying an already fragile cease-fire between them. Israel carried out airstrikes in southern Lebanon, killing at least four people, Lebanon’s health ministry said. The Israeli military later said that some rockets had been launched into northern Israel but reported no casualties.