SAUDI ARABIA blamed Iran yesterday for Saturday’s Yemeni missile attack on Riyadh — calling it an “act of war.”

The Saudi-led invasion coalition closed all land, sea and air routes into its southern neighbour yesterday in response to the launch of a Yemen-made Volcano H-2 missile.

Saudi Arabia claimed it shot down the missile with US-supplied Patriot missiles, but the de-facto Houthi-backed government in Yemen’s capital Sanaa said it hit Riyadh airport.

“Iran’s role and its direct command of its Houthi proxy” meant the attack was a “blatant act of military aggression by the Iranian regime,” the coalition said yesterday.

The coalition command could consider the attack “an act of war against the Kingdom of Saudi Arabia,” it said.

And Saudi Arabia said it “reserves [the] right to respond to Iran in the appropriate time and manner.”

The nine-nation coalition and its ally Washington have repeatedly accused Tehran of backing the Yemeni Republican Guard and Houthi militia in the two-and-a-half-year war.

On Sunday, US President Donald Trump pre-empted the Saudis, saying: “A shot was just taken by Iran, in my opinion, at Saudi Arabia. And our system knocked it down.”

Iranian Revolutionary Guard commander Major General Mohammad Ali Jafari called Mr Trump’s comments “lies.”

He stressed that the missiles were made in Yemen and said Iran has no means of supplying such arms to the country.

The Saudi sabre-rattling followed the purge ordered by Crown Prince Mohammed bin Salman on Saturday, in which 11 lesser princes and 38 officials and businessmen were arrested.

Yesterday another prince, Mansour bin Muqrin, was killed along with seven others in a helicopter crash in southern Asir province, where he was deputy governor.

Mr Mansour’s father and former spy chief Muqrin bin Abdulaziz was crown prince until 2015, when King Salman removed him in favour of Prince Mohammed bin Nayef, who was replaced by the king’s son Mohammed in June.

Yesterday the King swore in new National Guard chief Prince Khalid bin Ayyaf al-Muqrin and new Economy and Planning Minister Mohammad al-Tuwaijri.