KYIV – A leaked recording of an exchange between an Iranian air-traffic controller and an Iranian pilot purports to show that authorities immediately knew a missile had downed a Ukrainian jetliner after takeoff from Tehran, killing all 176 people aboard, despite days of denials by the Islamic Republic. Ukraine President Volodymyr Zelenskiy acknowledged the recording's authenticity in a report aired by a Ukrainian television channel Sunday night. In Tehran on Monday, the head of the Iranian investigation team, Hassan Rezaeifar, acknowledged the recording was legitimate and said it was handed over to Ukrainian officials. After the Jan. 8 disaster, Iran's civilian government maintained for days that it didn't know the country's paramilitary Revolutionary Guard, answerable only to Supreme Leader Ayatollah Ali Khamenei, had shot down the aircraft. The downing of the jetliner came just hours after the Guard launched a ballistic missile attack on Iraqi bases housing U.S. forces in retaliation for an earlier American drone strike that killed the Guard's top general, Qassem Soleimani, in Baghdad.

On Sunday, police said both individuals had cooperated fully and were no longer suspects, adding that they were continuing to follow leads in their investigation. The airport offered a £50,000 ($63,200) reward for any evidence that leads to the conviction of those responsible for the disruption, police said. Drone use around commercial flights is a growing safety concern for regulators. Prosecutions when drones are flown too close to commercial planes are rare, and some instances of drone sightings by commercial airliners have turned out to be inaccurate. This month, authorities in Mexico investigated a potential collision of an Aeromexico jetliner with a drone.

Boeing is looking ahead to a brave new world where jetliners fly without pilots and aims to test some of the technology next year, the world's biggest plane maker said in a briefing ahead of the Paris Airshow. The idea may seem far-fetched but with self-flying drones available for less than $1,000, "the basic building blocks of the technology clearly are available," said Mike Sinnett, Boeing's vice president of product development. Jetliners can already take off, cruise and land using their onboard flight computers and the number of pilots on a standard passenger plane has dropped to two from three over the years. Sinnett, a pilot himself, plans to test the technology in a cockpit simulator this summer and "fly on an airplane next year some artificial intelligence that makes decisions that pilots would make," he said. Self-flying aircraft would need to meet the safety standards of air travel, which had its safest year in 2016, according to the Aviation Safety Network.

The Pentagon, the world's largest user of drones, has posted a new policy on signs outside the mammoth five-sided building: No Drone Zone. The signs, complete with a red slash through an image of a quadcopter drone, reflect America's growing concern about the proliferation of the small, inexpensive remote-controlled devices and the risk they pose to safety, security and privacy. Federal law prohibits flying a drone anywhere in and around Washington, an area known as the National Capital Region. Other communities and institutions across the country are wrestling with the potential threat from more than 400,000 private and commercial drones now registered to operate in the skies. The pilot of a commercial jetliner said his plane nearly collided with a drone while approaching Los Angeles International Airport on Friday afternoon, sparking a search by L.A. police and sheriff's officials for the owner of the unmanned aircraft.