KYIV, Ukraine >> Russia has switched its aerial strike tactics to fool Ukraine’s air defenses, using decoy missiles without explosive warheads and deploying balloons, a senior Ukrainian official said Thursday.

“The Russians are definitely changing tactics” as the war approaches its one-year anniversary, Mykhailo Podolyak, an adviser to Ukrainian President Volodymyr Zelenskyy, said in an interview with The Associated Press.

The goal of the decoy missiles, Podolyak said, is to overwhelm Ukraine’s air defense systems by offering too many targets.

“They want to overload our anti-aircraft system to get an extra chance to hit infrastructure facilities,” Podolyak said, adding that Ukraine’s air defenses are adapting to the challenge.

In the interview, Podolyak also renewed Ukraine’s appeals for long-range missiles that would enable it to strike Russian troop concentrations far behind the front lines, and also stressed that “we just don’t have enough shells.”

He argued that speeded-up supplies of weaponry from Western partners would quicken an end to the war and said drawn-out war would favor Russia, not least because its population is more than three times that of Ukraine.

“A protracted war is the slow death of Ukraine,” he said. “Russia has enough time. Why? They will live in poverty. They always live like this. They don’t need comfort. They can live in a camp.”

But nearly a year into the Russian invasion, the human, economic and diplomatic costs are proving huge for Moscow. Its military difficulties include a growing shortage of missiles, Ukrainian and Western officials say.

Podolyak said Russia is facing “missile exhaustion” and that shortages are forcing its change in tactics. He said Russia is mixing older Soviet-era missiles with “new missiles that have some value.”

Moscow has not acknowledged problems with weapon supplies. But Britain’s Defense Ministry said in late November that Russia appeared to be stripping nuclear warheads off old cruise missiles and then firing the missiles as blanks at Ukraine. “Russia almost certainly hopes such missiles will function as decoys and divert Ukrainian air defenses,” it said.

Ukraine’s Western allies have progressively boosted the country’s air defenses in response to Russia’s expanded bombardments of the power grid and other targets. The changed Russian tactics — seen by some as evidence that Moscow is adapting its brute-force war strategy into something more nuanced — appeared to pay dividends Thursday when Russian forces fired 36 missiles in a two-hour overnight burst. Ukrainian air defense batteries shot down 16 of them — a lower rate of success than against some previous Russian waves.