US-Israeli attacks on Iranian cities have killed over 25 people from Sunday into Monday, while two people were found dead after missile attacks from Iran on Israel's Haifa.
Fresh attacks were reported on residential areas across Tehran on Monday as the Israeli army said it had completed a wave of strikes against "regime targets."
Gas outages hit parts of the capital after a strike on a university, according to Iran's state broadcaster IRIB.
Iran has ramped up attacks on its neighbours in the Gulf and Israel, as US President Donald Trump on Monday appeared to extend a deadline for the Islamic Republic to release its chokehold on the strategic waterway Strait of Hormuz.
Iran rejected Trump's threats and warned of "more devastating" retaliation if its civilian infrastructure is targeted.
"If attacks on civilian targets are repeated, the next stages of our offensive and retaliatory operations will be much more devastating and widespread," a spokesman for the Khatam al-Anbiya Central Headquarters said in a statement posted by state broadcaster IRIB on Telegram.
The warning came after Trump, in a social media post on Sunday, threatened to strike Iran if Tehran failed to meet his April 6 deadline to either reach a deal or reopen the Strait of Hormuz.
"Tuesday will be Power Plant Day, and Bridge Day, all wrapped up in one, in Iran. There will be nothing like it... Open the F------ Strait, you crazy b-------, or you’ll be living in HELL – JUST WATCH,” Trump wrote in a post on his Truth Social platform.
However, in a later post, Trump appeared to extend his deadline by 24 hours. "Tuesday, 8:00 P.M. Eastern Time!" Trump wrote without mentioning Iran or any other details.
Shortly after his Truth Social post on Sunday, Trump gave an interview to Fox News where he said, "If they don’t make a deal, and fast, I’m considering blowing everything up and taking over the oil."
Israel strikes on Lebanon kill at least 15
Israeli strikes on Lebanon killed at least 15 people Sunday and wounded 39, Lebanese officials said.
One of Israel's strikes in Beirut on Sunday killed at least five people and wounded 52 in the Jnah neighbourhood, according to the Lebanese health ministry, while a strike targeting an apartment building in Ain Saadeh town east of Beirut killed three people and injured three others.
A strike in the southern town of Kfar Hatta, far from the border with Israel, killed seven people, including a four-year-old girl, the ministry added.
Iran strikes Israel, Arab countries
Israeli firefighters were searching for two missing people in the rubble of a residential building in the northern city of Haifa after it was struck by an Iranian missile that killed two others, authorities said Monday.
The direct hit on a seven-storey building tore through sections of the structure, which has partially collapsed, the military and rescue services said.
Israel's emergency service, Magen David Adom, said four people were wounded in the strike, including a 10-month-old baby who suffered a head injury.
An 82-year-old man was also in a "serious condition", MDA said. A hospital later said he was stable.
On Monday, the military detected fresh waves of missiles fired from Iran, and each time it said its "defensive systems are operating to intercept the threat."
Kuwait and the UAE also reported missile and drone attacks from Iran.
Falling debris from an intercepted attack injured one person in an industrial area of Abu Dhabi, UAE authorities said on Monday.
"Abu Dhabi authorities have responded to an incident of falling debris on the Raneen Systems company in ICAD (Industrial City of Abu Dhabi) in the Musaffah area, following a successful interception by air defence systems," the Abu Dhabi government's media office posted on X.
"The incident resulted in moderate injuries to a Ghanaian national."
The injury comes a day after authorities in the Emirati city of Sharjah said they were "dealing with an incident that targeted Khor Fakkan" after the key port was targeted in the Gulf of Oman.
(With inputs from AP, AFP)