KYIV — Ukraine is racing to develop a new generation of low-cost interceptors after Russia began using turbojet-powered attack drones that can travel far faster than the propeller-driven aircraft deployed against earlier models. The newer drones, identified by Ukrainian officials as variants of Russia’s Geran series, are shrinking the time available for air-defense crews to respond and increasing pressure on a system already stretched by repeated nighttime attacks. Their targets have included passenger trains, warehouses, supply routes, homes and shopping centers, according to Ukraine’s defense-innovation platform Brave1. The stakes are especially high ahead of winter, when Ukraine will need to protect cities and critical infrastructure while preserving its most expensive air-defense weapons for Russian ballistic and cruise missiles. Using fighter jets or costly missiles against swarms of relatively inexpensive drones could rapidly deplete those defenses. “Together with dozens of Ukrainian companies, we are already looking for cheap and mass-produced solutions,” Defense Minister Evgeniy Khmara said last week during a meeting with Ukraine’s allies. He said some interceptors are already being tested in combat. More than 60 Ukrainian defense producers are working on the problem. President Volodymyr Zelenskyy said earlier this month that three to five companies had demonstrated promising results and that the next step was mass production. The newest Russian drones reportedly reach speeds of up to 600 kilometers per hour, compared with roughly 200 kph for older Geran-2 aircraft. They also fly at higher altitudes and produce less heat, making them harder for some detection and interception systems to track. Many Ukrainian interceptor drones top out at about 300 kph, leaving fighter aircraft to handle some of the faster targets. Ukrainian military intelligence has estimated that Russia can manufacture about 3,000 of the newest Geran-4 and Geran-5 drones each month. “And there are not enough interceptor missiles for all the jet-powered drones Russia sends against Ukraine,” said Andriy Zahorodnyuk, a former Ukrainian defense minister who leads the Center for Defense Strategies. He said the faster drones fly higher and move more quickly than the Shahed-type aircraft Ukraine had been working to counter. Ukrainian companies are testing several approaches. Brave1 said some high-speed quadcopters can reach about 550 kph, enough to intercept older jet-powered drones such as the Geran-3, which is reported to reach around 500 kph. The newest aircraft require a different class of weapon, according to Oleksii Babenko, chief executive of Vyriy Industries. Babenko said Ukraine is pursuing turbojet-powered interceptors, electrically powered impeller aircraft, high-speed racing-style quadcopters and systems designed to hit incoming drones head-on. His company and Noctis presented a high-speed interceptor in June that has produced encouraging results against jet-powered targets. Brave1 is also developing small anti-aircraft missiles, although those systems are more difficult to design than the simpler counter-drone weapons used against older Shaheds. Until cheaper systems are ready, Babenko said, Ukraine may have to rely on fighter-launched missiles or guns positioned near targets. “Logistics, procurement, production will also take some time,” Babenko said. “For a month or two, we will have to shoot them down with more expensive means.” The contest reflects a broader cycle of adaptation in the war, with artificial intelligence, satellite communications, electronic warfare and missile technology changing as each side responds to the other. Babenko said Ukraine’s defense industry had been warned that faster drones were coming but lacked the engineers and financing to prepare at the necessary speed. “The war doesn’t always give everyone time,” he said. Zelenskyy has urged allies and domestic manufacturers to accelerate work on air defense, saying Ukraine cannot wait while Russia expands its ability to attack civilians. Brave1 called the jet-powered drones a serious challenge but said Ukraine would develop a response.