Saudi authorities issued their first air raid alert in the capital since fighting returned to neighbouring Yemen, after explosions rang out in the early hours of Saturday.

Yemen's Houthis have staged a lightning offensive this month, seizing swathes of territory in one of the world's poorest countries, leaving the internationally recognised government, which is backed by Saudi Arabia, scrambling to respond.

Saudi Arabia itself, one of the region's powerhouses, has conducted scores of airstrikes on Houthi-held areas but failed to stop the advance. It has also sought help from its ally, the United States, but that has not materialised.

This is the first time since Yemen's long-standing civil war resumed that it has threatened the Saudi capital, further shaking a global economy already under pressure by nearly seven months of war between the US and Iran.

"The area is under a hostile aerial threat," said a message received just before 3:00 am by Riyadh residents, urging them to stay indoors.

The incident comes days after Riyadh accused the Houthis of targeting Mecca on Wednesday, denouncing it as a "cowardly terrorist attack" on Islam's holy city, which welcomes millions of pilgrims each year, both Sunnis and Shias.

The Iran-backed Houthis strongly denied the accusation, calling it a "worn-out lie".

The group has reported scores of retaliatory strikes carried out daily by Riyadh since their lightning offensive this month to take over the country's entire Red Sea coast, giving them control over the vital Bab al-Mandab strait.

Riyadh was targeted with waves of attacks during an earlier iteration of the war, including a drone strike on the US embassy in the capital's diplomatic quarter in March.

The United States, according to Axios, last week refused to strike the Houthis at Saudi Arabia's request.

On Thursday, Washington approved a US$24.3 billion sale of 48 F-35 fighter jets to the kingdom to help Riyadh "deter current and future threats", the US State Department said. (AFP)





Edited by Azam Khan