Three people were killed Wednesday in attacks on two Saudi Arabian airports that Yemen's Iran-backed Houthi rebels say they carried out, according to Saudi officials quoted by the Associated Press. The strikes mark a deadly turn in a conflict that has steadily drawn the kingdom further into what the AP describes as the latest front in the wider Iran war.

What happened at the airports

Saudi Arabia's civil aviation authority did not name a culprit for the attacks at Abha airport in the country's southwest and at King Khalid International Airport in Riyadh, but the Houthis had already claimed responsibility. Officials said the Abha attack killed a Moroccan resident and an Algerian resident and wounded 28 others. At King Khalid, a Sudanese national was killed and eight people were hurt.

The AP reported that new cage-like fencing has gone up around fuel tanks and other equipment belonging to state oil company Aramco near the Riyadh airport after a week of attacks on the capital. The spokesperson for the Saudi-led coalition, Maj. Gen. Turki al-Malki, said coalition forces shot down a ballistic missile north of Riyadh and destroyed a launch platform in Sanaa, Yemen's rebel-held capital. The AP said it could not independently confirm those claims.

A fight over a crucial strait

The airport strikes come as Saudi Arabia and allied Yemeni government forces press a major ground and air offensive to retake ground along Yemen's western Red Sea coast and the Bab el-Mandeb Strait, which the rebels seized about a month ago. Roughly 12% of global trade passes through the strait, and with shipping through the Strait of Hormuz curtailed by the Iran war, the Red Sea route has become even more important.

The two sides are giving conflicting accounts on the ground. Coalition officials said Monday that their forces had recaptured several key areas around the strait, while two Houthi officials claimed Wednesday that the rebels had retaken the town of Dhubab, the nearby village of Al-Jadid and the strait itself. A Yemeni government official denied that, and the AP could not verify either side's claims.

The Institute for the Study of War, a Washington think tank, wrote that the Houthis appear to believe that hitting civilian infrastructure such as oil sites and airports will raise Saudi Arabia's economic costs enough to force concessions.

The human toll

The renewed fighting has shattered a truce that held for four years. According to the United Nations, almost 1,000 people have been killed in the latest round and more than 200,000 have been displaced. The World Health Organization said this week that cholera and malnutrition cases are rising and that some hospitals are short of surgical supplies.

Separately, the Houthis fired missiles early Wednesday toward Aden, home to Yemen's internationally recognized government. Aden security officials said two missiles targeted the airport and caused no casualties, and a flight from Cairo landed safely shortly afterward.