The free-fall collapse of Yemen’s US-and-Saudi-Arabia-backed regime seems to be escalating from a civil war into a regional conflict, as Saudi Arabia began amassing military assets on the border to Yemen Tuesday and initiated a series of intense air strikes against the Iranian-backed Houthi rebels in Yemen on Wednesday. The United States recently pulled troops and diplomatic staff out of Yemen as Shiite Houthi rebels, backed by troops loyal to former Yemeni President Ali Abdullah Saleh, rapidly deposed Yemeni President Abdu Rabbu Mansour Hadi, who fled Aden and went into hiding in neighboring Djibouti.

The New York Times notes that the Houthi rebels took the Al Anad air base, which had been used by US counter-terrorism troops up until their recent evacuation, and subsequently launched air strikes with stolen Yemeni Air Force planes against Hadi’s home. This follows reports that Yemeni insurgents have likely obtained $500 million worth of US weapons that had been donated to Hadi’s regime in an effort to fight al-Qaeda terrorists in the region.

With Hadi on the run and Iranian-backed Shiite rebels threatening to conquer Yemen, a majority Sunni nation, neighboring Sunni superpower Saudi Arabia has officially made the decision to intervene, launching air strikes on an airport and air base near Sanaa, Yemen’s Houthi-overrun capital. The above-embedded Inform video footage points out the fact that Saudi Arabian officials say that the nation, backed by a coalition of 10 allies, is ready to send as many as 150,000 troops into Yemen. Sudan, Pakistan, and Jordan have also offered to contribute ground troops to Saudi Arabia’s attacks in Yemen, and Egypt is rumored to be considering joining the effort. US officials said that the Saudi Arabian bombing campaign was bolstered by logistical and intelligence support from the United States. Early reports place the death toll caused by the Saudi strikes at 13.

Meanwhile, Iran has condemned Saudi Arabia’s intervention, setting up a likely proxy war, as Iran is a rumored benefactor of the Houthi rebels’ assault on the Hadi regime. Anger over US drone strikes has been cited as a spark that contributed to the genesis of the Houthi uprising.

As the conflict widens throughout the region, al-Qaeda and ISIS lurk beneath the surface, working to capitalize on the chaos by launching attacks on the Houthi rebels in an attempt to occupy the power vacuum created by Hadi’s de-facto self-imposed exile.