SANAA-- Yemen's Shi'ite Houthi rebels say they have fired a barrage of ballistic missiles on the Saudi Defence Ministry in Riyadh and on an oil installation of Saudi oil giant Aramco in the Saudi border region of Najran.

"The rocketry forces of the Yemeni (Houthi) army and popular forces have already fired a barrage of long-range ballistic missiles, Burkan-H2, toward the headquarters of the Saudi Defense Ministry in the capital Riyadh," the Houthis said in a statement posted on the Houthi-controlled Saba news agency Wednesday.

"Other several ballistic missiles were fired toward the headquarters of the Saudi oil giant Aramco in Saudi border region of Najran," the Houthis added.

Houthis said the barrage of missiles also targeted King Abdullah City in the Saudi border province of Jizan.

However, the Saudi Arabiya television channel reported that Saudi air defence forces had intercepted and destroyed several ballistic missiles over the capital Riyadh, and southern provinces of Jizan and Najran.

Hours earlier, the Houthis said that they had launched drone air strikes on a facility run by oil giant Saudi Aramco in Najran and on a civil airport in Abha city in the Saudi border province of Asir.

However, the Saudi company tweeted that its establishments were operating "normally and safely."

Al Arabiya TV reported that the Saudi air defence forces had shot down the drones over Abha city and Jizan province.

Houthis have recently intensified such attacks with the completion the third year of Saudi-led war against the Iranian-allied militias in Yemen.

A day earlier, Houthis said they fired TWO ballistic missiles; one on a military camp in Asir and the other on a military camp in Jizan.

In March 2015, Saudi Arabia led a military coalition of Arab forces, backed by the United States, to intervene in Yemen's conflict to back the government of exiled President Abd-Rabbu Mansour Hadi.

The coalition has launched thousands of airstrikes on the Iran-aligned Shi'ite Houthis, in attempts to drive the rebels and reinstate President Abd-Rabbu Mansour Hadi in the capital, Sanaa.

In return, Houthis have fired hundreds of ballistic missiles toward Saudi cities, with most of them intercepted by Saudi air defence forces.

The war has so far killed more than 10,000 Yemenis, mostly civilians, and pushed the Arab country to the brink of mass famine.