Iran said on Sunday that it struck an unmanned U.S. military boat in the Strait of Hormuz, marking the latest exchange of fire between the countries after a month of relative calm.

Meanwhile, Israeli strikes in southern Lebanon killed four people and injured at least 20, including children, according to Lebanese authorities, near an area that has become a flash point in fighting between Israel and the Iran-backed militant group Hezbollah.

Iran says it hit a US boat in latest Hormuz salvo

State-run media in Tehran said the U.S. vessel was trying to enter a restricted area in the Strait of Hormuz.

U.S. Central Command, which oversees the U.S. military operations in the Middle East, did not confirm the claim or respond to request for comment. It comes one day after the U.S. said it struck Iranian oil tankers in retaliation for Iran launching ballistic missiles at Navy warships

Iran also said over the weekend it had targeted three tankers trying to transit the strait without permission.

Attacks resumed last week after roughly a month of quiet.

The war began with U.S. and Israeli attacks on Iran on February 28. But since a ceasefire agreement was announced in June, on-and-off fighting has persisted with both sides trying to inflict military and economic pain as negotiations have collapsed.

US President Donald Trump has said he wants to strangle Iran’s economy, even as he has struggled to bring the confrontation to a close. On Friday, he called the conflict, in which 18 US service members have died, “small potatoes,” while Vice President JD Vance said he “wouldn’t call it a war” at all.

Polls show Americans are giving Trump poor marks for his handling of the situation, which has seen energy prices spike and put the president’s fellow Republicans in danger of losing control of Congress in November’s midterm elections.

Separately, Israeli strikes killed at least four people in southern Lebanon on Sunday, Lebanon’s Health Ministry said.

Strikes on the Lebanese village of Arabsalim killed two, the ministry said. Another two were killed in the city of Nabatiyeh, near a strategic hill that Israel said Thursday was under its control.

At least 20 others were wounded in the Sunday strikes, the ministry said, among them three children and five women. The strikes also leveled a hospital that was not in use and was empty, the city rescue services told The Associated Press.

The Israeli military said its latest strikes came in response to a drone attack launched earlier Sunday by Hezbollah on Israeli troops in southern Lebanon. It did not respond when asked about the hospital.

Since a ceasefire went into effect between Israel and Hezbollah more than two months ago, fighting has subsided in much of Lebanon but low-level skirmishes and Israeli strikes continue.