The United States expanded the scope of its strikes on Iran on Monday, targeting provinces around the country, including a city hosting a nuclear power plant, as Tehran kept up its attacks in the region.
The Middle East war resumed after a weeks-long lull prompted by a memorandum of understanding (MOU) signed in June.
Oil prices surged to a one-month high on Monday as the foes battled to control the vital Strait of Hormuz.
As its truce with the US collapsed, Tehran reimposed its blockade of the waterway through which a fifth of world oil supplies transited prior to the war, while Washington retaliated by again blockading Iran's ports.
While the US had focused its strikes since the return to war mainly on areas near Hormuz, on Monday attacks hit provinces elsewhere in the country, including in the centre and the north, according to state media and local authorities.
In Bushehr, home to the country's only operational civilian nuclear power plant, Governor Mohammad Mozaffari told state news agency IRNA: "A few minutes ago, several locations in Bushehr city were hit by the American enemy's projectiles."
The last attack on Bushehr was on Friday night, as Iranian media reported explosions were heard in the city.
In East Azerbaijan province in the north, the head of the local crisis management unit, Majid Farshi, told IRNA that one person was killed and several others injured in an attack there.
Despite the latest attacks, Iranian foreign ministry spokesperson Esmaeil Baghaei said diplomatic exchanges with the United States via mediators were ongoing.
"Ideas have been conveyed to us by certain mediators," he told a press conference in Tehran.
Ship on fire
In the Strait of Hormuz, meanwhile, sailors abandoned a vessel that caught fire after an attack, according to the UK Maritime Trade Operations agency.
"The vessel was struck by an unknown projectile. The crew safely abandoned the vessel and have been recovered by a tug boat. The fire has not been extinguished, and the vessel is currently adrift," UKMTO said.
Iran's Revolutionary Guard had earlier said that two oil tankers trying to transit the strait "exploded and were brought to a halt", according to a statement reported by Tasnim news agency.
On Sunday, US Secretary of State Marco Rubio called on countries around the world to share the burden of protecting global shipping.
"It's clear that Iran, at least some people in Iran, want to control the straits and hold that as leverage against the world," Rubio told reporters.
"The United States will do and continue to do what it needs to, to protect global shipping, but other countries need to begin to step up and provide, whether it's hardware or finances, to help carry that burden," he said.
US Central Command (CENTCOM) said on Sunday that it successfully completed the ninth consecutive night of strikes against Iran, while Rubio said he would "continue to try" to reach a diplomatic solution.
The fresh fighting came after a weekend in which the US announced three new US military fatalities and one service member missing in action.
Two were killed during Iranian missile and drone attacks on Jordan on Friday, while another service member died in northern Iraq during the controlled detonation of unexploded ordnance from a downed Iranian drone, CENTCOM said.
President Donald Trump said on Sunday the latest US strikes on Iran "hit them very hard" in honour of the American fatalities.
The deaths brought to 17 the confirmed number of American military fatalities since the conflict began in February this year.
On Friday, Iran's health ministry reported that 50 people had been killed in recent fighting and more than 500 wounded.
Iran strikes US assets in the region
Iran's Revolutionary Guard announced on Monday that they had hit targets in Syria, Jordan and Kuwait overnight.
In Syria, Iranian forces launched "a surprise attack on the enemy special operations command centre in the Al-Tanf region", according to a Guard statement carried by state media.
The US said it withdrew its troops from Tanf in February.
In Jordan, the Guard said it targeted US military aircraft stationed at Aqaba Airport "with ballistic missiles, causing severe damage to a number of them".
The Guard also said they hit US military targets based in Kuwait, including an early-warning radar system that was "completely destroyed".
Kuwaiti air defences were "engaging hostile drone attacks following Iranian aggression", its army said on Monday.
Bahrain's interior ministry also said that its air raid sirens had sounded and urged citizens and residents to head to "the nearest safe place".
