The Iran-linked rebels have stepped up attacks on neighbouring Saudi Arabia, mainly targeting southern provinces along the long border between both countries.

But on Thursday afternoon, the rebels' Al-Masirah television said the Huthis attacked an "important target" in Riyadh using drones and a missile.

The coalition did not confirm an attack on Riyadh and the city's resident did not report any visible signs of an assault.

But hours later, coalition spokesman Turki al-Maliki said it intercepted and destroyed a "number of ballistic missiles and bomb-laden" drones launched towards the kingdom.

He did not specify the target nor report any damage or casualties.

"The terrorist Huthi militia is deliberately escalating the hostile, terrorist targeting of civilians and civilian objects using ballistic missiles and bomb-laden (unmanned aerial vehicles)," Maliki was quoted as saying by the official Saudi Press Agency.

Huthi rebels have targeted Riyadh in the past with missiles and drones, with the coalition claiming to intercept most of them.

The coalition, assisted by Western powers including the US, has struggled to oust a ragtag but highly motivated tribal militia that specialises in guerrilla tactics.

Saudi Arabia has repeatedly accused Iran of supplying sophisticated weapons to the Huthis, a charge Tehran denies.

The coalition intervened in support of the Yemeni government in 2015 after the Huthis seized the capital Sanaa and closed in on the government's temporary base of Aden.

Since then, tens of thousands of people, mostly civilians, have been killed and millions displaced in what the United Nations has called the world's worst humanitarian disaster.