The top US general says the United States is carrying out strikes against Iranian mine-laying vessels.
The war has effectively shut the Strait of Hormuz, a choke point for global oil and liquefied natural gas transport, leaving tankers unable to sail for more than a week and forcing producers to halt pumping as storage fills.
"(US Central Command) continues today to hunt and strike mine-laying vessels and mine storage facilities," General Dan Caine, chairman of the Joint Chiefs of Staff, told reporters.
Caine added that in the first 10 days of the campaign against Iran, the US had sunk or destroyed more than 50 naval ships.
The Strait of Hormuz will either be a strait of peace and prosperity for all or a strait of defeat and suffering for "warmongers," Iranian security chief Ali Larijani said in a post on X on Tuesday.
Iran has threatened to block the narrow waterway in response to any attack.
US President Donald Trump on Monday threatened to escalate the war with Iran if it blocked oil shipments from the Middle East, even as he predicted a quick end to the conflict.
US Defense Secretary Pete Hegseth said the United States would carry out the most intense day of strikes against Iran on Tuesday.
Hegseth told reporters Tuesday would bring the most fighter jets and bombers against Iran.
"We will not relent until the enemy is totally and decisively defeated," he said.
"For example, today will be yet again, our most intense day of strikes inside Iran. The most fighters, the most bombers, the most strikes, intelligence more refined and better than ever," Hegseth said.
He noted also that the last 24 hours had "seen Iran fire the lowest number of missiles they've been capable of firing yet".
On Saturday, Trump said Iran would be "hit very hard" and that the country was already "being beat to hell" by ongoing US and Israeli attacks.
Larijani wrote on X that Iran is not afraid of threats and that even larger countries have not been able to destroy Iran.
"Watch out yourself that you are not wiped out," wrote Larijani, who is secretary of the Supreme National Security Council.
Iran launched new attacks on Tuesday at Israel and Gulf Arab countries as it kept up pressure in the war started by Israel and the US.
In Bahrain, authorities said an Iranian attack hit a residential building in the capital Manama, killing a 29-year-old woman and wounding eight people.
Saudi Arabia said it destroyed two drones over its oil-rich eastern region and Kuwait's National Guard said it shot down six drones.
In the United Arab Emirates, firefighters battled a blaze in the industrial city of Ruwais - home to petrochemical plants - after an Iranian drone strike, officials said.
No injuries were reported.
Sirens also sounded in Jerusalem, and sounds of explosions could be heard in Tel Aviv as Israel's defence systems worked to intercept barrages from Iran.
with DPA and AP