Yemen's Houthis reported fresh Saudi airstrikes on Wednesday, as Riyadh accused the group of launching a "cowardly" attack targeting Islam's holy city of Mecca.

The Houthis swiftly rejected as a "lie" Riyadh's early morning statement that it had shot down a drone heading towards Mecca, but the accusation prompted a chorus of outrage from around the Muslim world.

Renewed fighting between the Houthis and Yemen's Riyadh-backed government has dragged in the kingdom, after the Houthis declared a maritime blockade on Saudi ships in the Red Sea.

Last week, the Houthis seized control of the entirety of Yemen's Red Sea coast and the Bab al-Mandab Strait, a vital artery for Saudi oil exports as the wider Middle East war chokes off the Strait of Hormuz shipping route.

Saudi Arabia's foreign ministry condemned the targeting of Mecca as a "cowardly terrorist attack" and reaffirmed the kingdom's right to "defend the security of the two holy mosques, the pilgrims, and the entire Saudi territory".

Houthi politburo member Hazem al-Assad, however, dismissed the accusation as "a worn-out lie that has been used before and no longer fools anyone".

One Mecca resident who spoke to AFP on condition of anonymity said they "saw a few people panicking, running to the window to see what happened" after locals received an alert on their phones warning of an attack.

But, they added, "life is normal in Mecca".

Saudi Arabia has accused the Houthis of launching attacks towards the city in an earlier conflict.

The Saudi-led coalition battling the group vowed retaliation, saying "the security of the Two Holy Mosques and the pilgrims is a red line".

"The coalition will not hesitate to take the necessary and deterrent measures against the Terrorist Houthi Militia."

On Wednesday evening, Houthi military spokesman Yahya Saree said "Saudi warplanes launched 40 airstrikes... targeting the provinces of Taiz, Marib, and Hodeidah over the past 24 hours".

He had previously put the number of Saudi strikes launched over the past week at more than 450, saying that in response, the group had targeted a Saudi air base and a state oil company facility in the Red Sea port city of Yanbu.

The group also claimed on Wednesday to have shot down a Saudi fighter jet.

'Aren't they Muslims?'

Saudi Arabia had issued alerts on Tuesday warning of possible attacks in Mecca and across parts of the south.

"I won't hide that we were scared," another Mecca resident said on condition of anonymity.

"Aren't they Muslims? They're targeting the holiest city. What's inside to target?"

During this year's hajj pilgrimage, the Saudi defence ministry released a video showing advanced air defence batteries positioned on the outskirts of Mecca.

The Organisation of Islamic Cooperation -- a bloc of 57 Muslim countries -- condemned the "heinous attacks", while Arab League chief Nabil Fahmy called it "a matter of extreme gravity".

The governments of Egypt, Lebanon, Syria and Pakistan also voiced outrage.

Yemen's civil war has been largely dormant since 2022, but fighting flared in July when the Houthis, who have for years controlled swathes of the north, launched a large-scale offensive against government forces.

The conflict in the Arabian Peninsula's poorest country has forced more than 100,000 people to flee their homes, according to the United Nations.

Yemen's permanent representative at the UN, Abdullah al-Saadi, said the government was fighting to restore "national institutions across every inch" of the country, and called on the international community to take action against the Houthis.

Clashes near the border

Yemeni government forces are clashing with Houthi fighters near the Saudi border, with AFP footage showing soldiers in armoured vehicles and trucks pushing across desert terrain under the crackle of machine-gun fire.

Two military sources told AFP on Wednesday that government forces were fighting the Houthis for control of Al-Labanat camp, whose capture would theoretically clear the path to Al-Hazm, the capital of Al-Jawf governorate, 50 kilometres (30 miles) away. 

With the Houthis targeting Saudi ships in the Red Sea, the kingdom's de facto leader Crown Prince Mohammed bin Salman and Egyptian President Abdel Fattah al-Sisi called on Tuesday for free navigation in the waterway, which serves as a gateway to the Suez Canal, a crucial source of revenue for Cairo.

US media reported last week that the crown prince made a personal request to President Donald Trump for US intervention, but was turned down.

A US military task force is working to enhance intelligence-sharing and planning assistance for Saudi forces, a US official told AFP on Tuesday.

The Houthis have insisted there is no threat to navigation in the Bab al-Mandab Strait except for Saudi vessels, but any attacks in the waterway are likely to make it less attractive to shippers.