The US military launched new strikes against Iranian targets on Tuesday after Washington accused Tehran of attacking ships in the Strait of Hormuz.
The latest military action has cast fresh doubt on the durability of a ceasefire that has been in place for three months, and comes even as the two sides attempt to hammer out a long-term peace deal.
Central Command said its forces hit over 80 Iranian targets, striking more than 60 Islamic Revolutionary Guard Corps small boats, air defence systems, command and control networks, coastal radar sites and anti-ship missile capabilities.
The action came in response to Iran attacking three commercial vessels transiting the Strait of Hormuz, Centcom said, accusing Iranian forces of a "clear and dangerous violation" of the ceasefire.
"Centcom forces remain postured and prepared to hold Iran accountable when the agreement is not adhered to or obeyed," Centcom said in a statement.
Iranian state media reported explosions in Bandar Abbas, Qesh, Sirik and other areas.
Reports on social media included video of what were said to be fires burning at the port in Bandar Abbas on the Strait of Hormuz.
The US earlier said it was revoking a general licence that authorised the sale of Iranian oil, putting new economic pressure on Tehran after it was blamed for recent attacks on tankers in the Strait of Hormuz.
A US official warned Iran's actions in the waterway were "wholly unacceptable" and "will be met with consequences".
Qatar's Foreign Ministry on Tuesday said Doha holds Iran "fully legally responsible" for an attack that hit a Qatari LNG tanker in the strait, causing a fire in the engine room.
Al Rekkayat was one of two vessels reported to have been struck by missiles while transiting the waterway on Monday night.
The US and Iran declared a ceasefire in early April, and in mid-June the two sides signed an agreement aimed at bringing the war to a close.
Despite the agreement and promises to work towards peace, both countries have accused each other of breaching the ceasefire.
Tehran says the US has continued to launch attacks on Iranian territory and has allowed Israel to continue its war in Lebanon, while the US has highlighted Iranian mine-laying and drone attacks in the Strait of Hormuz.
The Iranian regime has in recent days put on a public show of force and defiance after the US moved to end the war it started on February 28 alongside Israel.
Talks were set to continue after the funeral processions. US President Donald Trump had said attacks would halt during the funeral.
Tehran's top leaders appeared publicly at funeral commemorations for Iran's former supreme leader, Ayatollah Ali Khamenei.
He was killed during the opening strikes by the US and Israel that also attacked a senior command meeting in Tehran.
Some among the throngs of mourners at this week's funeral events issued death threats against Mr Trump.
Oil prices, which had cooled considerably in recent weeks, jumped on news of the US attacks.
