"I personally apologise to neighbouring countries that were affected by Iran's actions," Iranian President Masoud Pezeshkian said, urging them not to join US-Israeli attacks on Iran.
He dismissed US President Donald Trump's demand for the Islamic Republic's unconditional surrender as "a dream" but said its temporary leadership council had agreed to suspend attacks on nearby states unless strikes on Iran originated from their territory.
Trump nonetheless cast Iran's apology as a surrender while saying the country would be "hit very hard" on Saturday and warned the US could widen its attacks to areas and groups of people that were not previously designated targets.
Pezeshkian's comments caused a political stir in Iran, prompting his office to reiterate Iran's military would respond firmly to attacks from US bases in the region.
Hamid Rasai, a hardline cleric and MP, wrote on X, "Mr Pezeshkian, your stance was unprofessional, weak and unacceptable".
Hours after Pezeshkian's announcement, Iran's Revolutionary Guards said their drones struck a US air combat centre at al-Dhafra Air Base, near the United Arab Emirates capital Abu Dhabi.
The Revolutionary Guards also targeted US forces at a base in Bahrain, the Iranian state media said.
Blasts were also heard in Doha, a Reuters witness said.
Gholamhossein Mohseni-Ejei, Iran's judiciary chief, said evidence from Iran's armed forces indicates that the territory of some regional countries was being used to carry out attacks against Iran.
Heavy strikes on those targets will continue, said Mohseni-Ejei, who is also a member of the interim leadership council set up after Supreme Leader Ayatollah Ali Khamenei was killed in an air strike on his compound at the start of the conflict.
Huge explosions were heard in several parts of the Iranian capital, state media reported.
The US-Israeli war on Iran has already spilled beyond Iran's borders as its forces responded by hitting Israel and Gulf Arab states hosting US military installations and Israel has launched fresh attacks in Lebanon after the Iran-aligned militia Hezbollah fired across the border.
Gulf states voiced outrage that their civilian infrastructure - hotels, ports and oil facilities - was struck despite their having had no part in the US-Israeli attacks.
The UAE, Kuwait, Qatar, Bahrain, Oman, Saudi Arabia and Iraq have all reported drone or missile attacks over the past week.
Iran had mended fences with its Gulf neighbours in recent years, including with former regional arch-rival Saudi Arabia.
An Emirati official said the United Arab Emirates wanted the Iranian aggression against the Gulf states to end immediately.
"We don't want the war to expand. We want to start with the Iranians realising that they are not helping themselves by attacking their whole neighbourhood and to stop there and realise that," the official said.
The US-Israeli attacks have killed at least 1332 Iranian civilians and wounded thousands, according to Iran's United Nations ambassador Amir Saeid Iravani.
Iranian attacks have killed 10 people in Israel, and at least six US service members have been killed.
Israel launched what its military described as a new wave of strikes on Tehran and Isfahan, while overnight, the Israeli military said it had carried out strikes on neighbouring Lebanon that it said were aimed at Hezbollah military sites.
The Israeli military reported identifying missiles fired from Iran at Israel on eight different occasions on Saturday, setting off air raid sirens in parts of the country and prompting Israeli air defences to intercept incoming fire.
