Armed militants loyal to Yemen’s President Abd-Rabbu Mansour Hadi ride a patrol truck in the country’s southern port city of Aden March 25. Photo: Reuters.

SANAA  —  Saudi Arabia announced on Wednesday it had launched military operations in Yemen, carrying out air strikes in coordination with a 10-country coalition seeking to beat back Houthi militia forces besieging the southern city of Aden where the country’s president had taken refuge.

At a news conference in Washington, Saudi Ambassador Adel al-Jubeir said Gulf Arab allies and others had joined with the desert kingdom in the military campaign in a bid “to protect and defend the legitimate government” of Yemen President Abd-Rabbu Mansour Hadi. He declined to give any information on Hadi’s whereabouts.

With the Saudi-led military assault, the Middle East’s top oil power has been drawn into the worsening Yemeni conflict.

The crisis risks spiraling into a proxy war with Iran backing the Houthis, whose leaders adhere to the brand of Shi’a Islam, and Saudi Arabia and the other regional monarchies backing Hadi.

“We will do whatever it takes in order to protect the legitimate government of Yemen from falling,” Jubeir said.

But he declined to give any information on the whereabouts of Hadi, though he said the military action was being taken at the embattled U.S.-backed leader’s direct request. The United States said earlier that Hadi, holed up in Aden since fleeing the Houthi-controlled capital Sanaa last month, was no longer at the compound he has been using as a base.

Jubeir said the United States was not participating in the military campaign but a U.S. official said Washington was providing some unspecified support. He said the mission would not be limited to a specific city or region of Yemen, suggesting that the coalition’s warplanes could strike the Houthis anywhere they choose.

Houthi militia forces and allied army units seized Aden airport and a nearby air base on Wednesday, tightening their grip on the outskirts of the southern Yemeni city.

“We were in touch with him earlier today,” State Department spokeswoman Jen Psaki told a briefing in Washington. “He is no longer at his residence. I’m not in position to confirm any additional details from here about his location.”

Residents later said looters had entered the residence hours after Hadi vacated it in mid-afternoon for an unknown location. Foreign Minister Riyadh Yaseen and Hadi’s aides said Hadi remained in Aden, in a safe place, without elaborating.

Local officials said troops loyal to Yemen’s ex-President Ali Abdullah Saleh, a powerful ally of the Houthis, had captured Aden airport in late afternoon but that clashes with Hadi supporters were continuing in the vicinity. The airport was closed and all flights were canceled.

The Houthis confirmed in a statement to reporters that Saudi jets hit a military base in Sanaa, known as al-Duleimi. They said they fired anti-aircraft missiles in response.

Mohamed Al-Bokhaiti, a member of the Houthi political office, called the military action as a declaration of war on Yemen.

Hakim Al Masmari, Yemen Post editor, said that “people are very terrified”.

“It’s [bombing] not in any particular location in Sanaa, it’s throughout the capital,” he said.

Earlier the Houthis and their allies took al-Anad air base 37 miles north of the city before continuing their southward advance.

Sunni Arab monarchies around the region have condemned the Houthi takeover as a coup and have mooted a military intervention in favor of Hadi in recent days.

U.S. officials said earlier that Saudi Arabia was moving heavy military equipment including artillery to areas near its border with Yemen. But Saudi sources said earlier on Wednesday that the build-up, which also included tanks, was purely defensive.