At least six Russian balloons floated over the Ukrainian capital, Kyiv, on Wednesday, triggering air-raid sirens before most of them were shot down, Ukrainian officials said, prompting speculation about the balloons’ purpose and when they were first deployed.
“About six enemy air targets were detected in Kyiv’s airspace,” said a statement from the Kyiv military administration, posted Wednesday on the Telegram social messaging app. “All six were hit by air defense systems. Most of these probes were shot down.”
The purpose of the balloons remains under investigation, it said, although given the conflict there seemed to be slightly less mystery about them than a Chinese balloon and other objects that have been detected recently drifting over North America.
Russia “uses such flying objects for reconnaissance or to confuse air defense systems,” Yuriy Ihnat, the spokesman for the Ukrainian air force, said on national television. Although the balloons are of different sizes, he said, they can be used to dangle aloft simple, small reflectors.
The rudimentary reflectors are meant to disorient missiles that use radar to home in on their targets. Russia has used the reflectors before to try to avert attacks on valuable targets like the Kerch Bridge, which connects Russia to Crimea, but it has not previously attached them to balloons.
Russia has not commented on the accusations from Ukraine or ones from neighboring countries that also have said they detected balloons.
It was not clear whether Russia just recently introduced the balloons in Ukraine, or whether they were previously considered so unremarkable that they drew attention only after the Chinese balloon and other unidentified objects were shot down over the United States in recent weeks.
On Tuesday, Mr. Ihnat reported the Russians on Sunday had used balloons over the eastern Dnipropetrovsk region. He said those appeared to be filled with gas and about one to one and half meters in diameter — just large enough to lift the reflectors.
In addition to reconnaissance and possible distraction, Mr. Ihnat said the Russians were trying to get Ukraine to expend valuable resources, including antiaircraft missiles, to shoot them down.
The balloons are hardly new. The Soviet military had a balloon program, which has continued under the Russian Federation, according to Michael Kofman, a military expert and the director of Russian studies at C.N.A., a research institute in Arlington, Va.
Experts in Ukraine and the United States suggested that the most likely reason for the balloons was to trigger Ukrainian air defense systems. That could reveal their location so that Russia could later target the positions for attack, or could prompt Ukraine to waste ammunition.
“It gets them to expend valuable defense ammunition on what, at the end of the day, are balloons,” Mr. Kofman said. The balloons are not terribly reliable for use in deflecting weapons, he added.
High-flying balloons that drift on air currents can be hard to detect. Radar systems used for territorial defense are generally designed to focus on incoming aircraft, missiles and other fast-moving objects. They are often set to avoid picking up things moving slowly, like balloons sent aloft to help predict weather patterns.
Elsewhere, Moldova briefly closed its airspace because of a presumed air balloon that entered its territory on Tuesday. The country’s government said it had closed the airspace for more than three hours to ensure the security of passenger flights after an “object similar to a weather balloon” was detected near the Ukrainian border.
The airspace was reopened once the object was found to be harmless, said Daniel Voda, a spokesman for the Foreign Ministry. The government did not specify the fate of the balloon.
Next door, Romania briefly scrambled military jets on Tuesday also due to a balloon, The Associated Press reported.