Another US combat drone has been shot out of the sky

A US military combat drone has been shot down over Yemen, marking the second time in three months the US has lost an unmanned aerial vehicle over the war-torn country.

Yemen's Houthi insurgency claimed responsibility, announcing that it downed a US MQ-9 Reaper hunter-killer drone, a $15 million unmanned aerial combat vehicle developed by General Atomics, in Dhamar, an area to the southeast of the Houthi-controlled capital of Sanaa.

"We are aware of reporting that a US MQ-9 was shot down over Yemen. We do not have any further information to provide at this time," US Central Command initially said in response to Insider's inquiries Aug. 20, 2019.

Two officials speaking to Reuters on the condition of anonymity confirmed the that a drone was shot down. While one said it was the Houthis, another cautioned that it was too early to tell.

"It's the Houthis, but it's enabled by Iran," another US official told Voice of America.

In a follow-up response to media questions, CENTCOM said Aug. 21, 2019, it is "investigating reports of an attack by Iranian-backed Houthis forces on a U.S. unmanned aircraft system (UAS) operating in authorized airspace over Yemen."

The US military has, to varying degrees, for years been supporting of a coalition of mostly Sunni Arab states, led by Saudi Arabia, fighting to restore the internationally-recognized government in Yemen as the Houthi rebels backed by Shia Iran push to topple it.

"We have been clear that Iran's provocative actions and support to militants and proxies, like the Iranian-backed Houthis, poses a serious threat to stability in the region and our partners," CENTCOM said in its statement Aug. 21, 2019.

The Houthis shot down an US MQ-9 in mid-June 2019 with what CENTCOM assessed to be an SQ-6 surface-to-air missile. The US believes that the rebel group had help from the Iranians.

"The altitude of the engagement indicated an improvement over previous Houthi capability, which we assess was enabled by Iranian assistance," CENTCOM said in a statement

An MQ-9 Reaper unmanned aerial vehicle flies a combat mission over southern Afghanistan.

(Photo by Lt. Col. Leslie Pratt)

Around that same time, Iranian forces fired a modified Iranian SA-7 surface-to-air missile at an MQ-9 in an attempt to "disrupt surveillance of the [Islamic Revolutionary Guard Corps] IRGC attack on the M/T Kokuka Courageous," one of the tankers targeted in a string of suspected limpet mine attacks the US has blamed on Iran, CENTCOM revealed, USNI News reported at the time. The Iranians failed to down the aircraft.

Toward the end of June 2019, Iranian forces successfully shot down a US Navy Broad Area Maritime Surveillance (BAMS-D) aircraft, specifically a RQ-4A Global Hawk high-altitude long endurance (HALE) drone operating over the Strait of Hormuz.

President Donald Trump had initially planned to retaliate militarily against Iran but cancelled the mission after learning that striking would result in significant Iranian casualties, which would make the response disproportionate as the Iranians attacked an unmanned system.

Tensions between Iran and the US have spiked in recent months, as Washington put increased pressure on Tehran, leading it to push back with carefully calculated displays of force just below the threshold of armed conflict. The Houthis in Yemen have taken shots at the US before, firing not only on US combat drones but also US warships.

This article originally appeared on Business Insider. Follow @BusinessInsider on Twitter.