Saudi Arabia, backed by other Gulf states and Egypt, launched airstrikes against Houthi militants in Yemen overnight after the country's president fled his palace ahead of advancing fighters.
President Barack Obama authorized logistical and intelligence support, National Security Council spokesperson Bernadette Meehan said in a statement. The U.S. will take no direct military action, she added.
"The United States strongly condemns ongoing military action taken by the Houthis against the elected government of Yemen," Meehan said.
Saudi Ambassador Adel al-Jubeir said the air campaign began at 7 p.m. Eastern time Wednesday.
"The use of force is always the last resort," al-Jubeir told reporters in Washington, D.C., Wednesday. Al-Jubeir said nine other countries have joined a coalition to prevent the Houthis from taking over Yemen, but did not name them.
"We will do whatever it takes in order to protect the legitimate government of Yemen from falling and from facing any dangers from an outside militia," al-Jubeir said. "We have a situation where you have a militia group that is now in control."
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The airstrikes come after reports that Yemeni President Abed Rabbo Mansour Hadi, a close U.S. ally, had fled his palace in Aden ahead of advancing Houthis, Shiite rebels seen by some to be backed by Saudi Arabia's arch-rival Iran. A senior unnamed Yemeni official told NBC News that he was still in the country.
The United Arab Emirates, Kuwait, Qatar and Bahrain joined Saudi Arabia in a statement published by the Saudi Press Agency, saying they would answer a request from Hadi for help. Egypt, in a statement through state media, also announced its political and military support for Yemen.
Two American officials told NBC News Saudi airstrikes were conducted near Sanaa Wednesday.
The Houthis said in a statement to reporters that Saudi jets are hitting a military base, known as al-Duleimi, in Sanaa. They said they fired anti-aircraft missiles in response.
The escalating situation prompted the U.S. to withdraw its advisers and intelligence officials from the country over the weekend.
— Phil Helsel
The Associated Press contributed to this report.