Saudi Arabia issued emergency warnings Tuesday for Jeddah, Mecca and Taif and vowed a firm response after Iran-backed Houthi missile and drone attacks wounded 13 people.
The alerts were issued through the National Early Warning Platform for Emergencies, according to the Saudi Civil Defense.
Authorities, however, did not specify the nature of the potential danger.
Residents were urged to remain calm and immediately move to the nearest safe place, preferably inside a building or an interior room away from windows and remain there until the danger passes.
The Civil Defense also advised people to stay away from open areas, windows, balconies and rooftops, while those outdoors were told to enter the nearest building or take shelter behind a solid barrier.
Motorists receiving an alert were instructed to pull over away from bridges and high-rise buildings, while the public was urged to avoid gatherings and dangerous areas and follow instructions through official channels.
'Firm response'
The alerts come amid escalating clashes between Saudi Arabia and Yemen’s Houthi group, which has carried out a series of missile and drone attacks on Saudi cities and infrastructure in recent days.
Saudi government vowed Tuesday to respond "firmly" after attacks by the Iran-backed rebels wounded 13 people in the kingdom in an assault using ballistic missiles and drones.
The Houthis have been engaged in renewed fighting with Saudi-backed government forces since Yemen's civil war reignited in July, when the group declared a maritime blockade on Riyadh and began targeting its ships in the Red Sea.
They seized control of Yemen's Red Sea coast and the Bab el-Mandeb Strait last week, which has become vital as the wider U.S.-Iran war chokes the Strait of Hormuz.
The Houthis have also targeted the oil infrastructure of Saudi Arabia, the world's leading crude exporter, pushing oil prices above the $100 threshold.
A Houthi strike in western Yemen on Monday killed eight government soldiers, according to two military sources.
The group also claimed a new large-scale attack using "dozens of ballistic missiles and drones" against King Khalid airbase in Khamis Mushait, in southern Saudi Arabia.
A Khamis Mushait resident told AFP he heard "intense blasts" which left fires burning for a "long time."
"Honestly, we couldn't sleep at all."
In the early hours of Tuesday, the Saudi civil defense issued air-raid alerts in six regions, before lifting them.
The Riyadh-led coalition confirmed Tuesday there had been missile and drone attacks the previous day on Khamis Mushait, Abha and Taif, reporting 13 civilians wounded and damage to seven houses and two vehicles.
Saudi Arabia responded with more than 50 strikes, as it had the day before, according to the Houthis.
The coalition said it would deal with the attacks "firmly to protect the sovereignty of the Kingdom" and would take "all necessary operational measures to deter this ... hostile and extremist approach."
While Saudi Arabia has conducted dozens of airstrikes on Houthi-held areas, it has failed so far to deter the rebels' lightning offensive.
Saudi Arabia's de facto ruler Crown Prince Mohammed bin Salman was expected to hold talks with Egypt's President Abdel-Fattah el-Sissi on Tuesday.
U.S. media reported last week that President Donald Trump had rejected a personal request from the Saudi crown prince to intervene in the war.
'No negotiations'
Hazem al-Assad from the Houthis' politburo said the "Yemeni response will continue and escalate as long as they (Saudi Arabia) persist in their aggression against our people."
The renewed fighting in Yemen comes as the wider regional war remains at a stalemate. But Trump Monday said he was open to holding talks with Iran.
"The failing Nation of Iran wants to make a deal, quickly and badly. I will determine whether or not the U.S.A. will choose to engage -- The concept of which we are open to," Trump said on his Truth Social network.
Iran's top security chief Mohsen Rezaei responded by saying on X that "there will be no negotiations until Iran's conditions are met. That is all there is to it."
Tehran has repeatedly listed demands including war reparations and the lifting of sanctions as preconditions for ending the war and its blockade of the Strait of Hormuz.
Wider regional war
A proposed meeting between Gulf states and Iran over the future of Hormuz was postponed on Monday, with Tehran accusing Riyadh of using Yemen as a pretext to delay the talks.
Tehran has long supported the Houthis, a member of its anti-Israel "axis of resistance," including with weapons and technology, but has denied any role in the current war.
"Iran does not interfere in Yemeni affairs," Foreign Ministry spokesperson Esmaeil Baghaei told reporters Monday, saying the Houthis are "entirely independent actors who make their decisions based on their own interests."
The Houthis seized Yemen's capital Sanaa in 2014 at the outset of the civil war, driving the government to Aden in the south.
The following year, Saudi Arabia led a coalition to intervene on the side of the government, launching wave after wave of airstrikes as the conflict escalated.