Three people were killed in attacks targeting two airports in Saudi Arabia, the kingdom’s General Authority of Civil Aviation said Wednesday.

The Saudi authorities did not blame any party for the attacks at Abha and Riyadh’s King Khalid international airports, but Iran-backed Houthi rebels in Yemen claimed earlier that they carried out attacks against the two airports.

The attack on Abha airport killed Moroccan and Algerian residents and wounded 28 other people, while the attack on King Khalid airport killed a Sudanese national and wounded eight other people, officials said.

As the Saudi capital is targeted again, new cage-like fences have been erected this week around fuel tanks and other equipment of the Saudi state-run Aramco oil company near the Riyadh airport. The kingdom, the world’s top oil exporter, has seen oil and military assets targeted in recent days.

The Houthis’ military spokesperson, Brig. Gen. Yahya Saree, said on social media that the rebels launched ballistic missiles and drones against King Khalid International Airport in Riyadh. The spokesperson for the Saudi-led coalition fighting the Houthis, Maj. Gen. Turki al-Malki, said they intercepted a ballistic missile north of Riyadh. Flights were briefly disrupted, according to Flightradar24.

Now Saudi Arabia and allied Yemeni forces have launched a major ground and air offensive aimed at retaking territory that the rebels seized a month ago along Yemen’s western Red Sea coast and on the Bab el-Mandeb Strait.

Those positions gave the Houthis better surveillance as they pursue a blockade of Saudi-linked shipping. On Monday, officials said forces of the Saudi-led coalition recaptured several key areas around the strait, through which about 12% of global trade transits.

"The Houthis believe that they can maximize Saudi economic costs and compel Saudi Arabia to surrender to Houthi demands by striking civilian infrastructure, such as oil facilities and airports,” the Institute for the Study of War, a Washington-based think tank, wrote in an analysis.

The Houthi spokesperson said they also targeted Abha airport in Saudi Arabia, a frequent target of rebel drones and missiles. The rebels also claimed to hit an air base in the city of Khamis Mushait and two military bases in Najran and Asir. All are in the southwest, near the Yemeni border.

Inside Yemen, fighting has centered in and around the crucial town of Dhubab, some 54 kilometers (33.5 miles) south of the port city of Mokha that the rebels seized last month, according to both the Houthis and Yemen's internationally recognized government.