Failure can range from false launches to rockets failing to explode on impact. The Pentagon estimates that Russia has shot down more than 1,100 missiles of all types since the war began. The three US officials estimated that Russia’s failure rate varies from day to day. Reuters was unable to independently verify the figures. The Russian Presidential Office and the Defense Ministry in Moscow did not immediately respond to a request for comment.

According to Reuters, one of the government officials said Russia’s air-launched cruise missiles had a failure rate of between 20 and 60 percent, depending on the day. According to the Institute’s Center for Strategic and International Studies Missile Defense Project, Russia has deployed two types of air-launched cruise missiles in Ukraine, the Kh-555 and the Kh-101. Experts interviewed by Reuters said that a default rate of 20 percent or more is considered very high.

According to US information, Russia fired cruise missiles from its own airspace during an attack on a Ukrainian military base near the Polish border in early March. The failure rate was particularly high in this attack. According to the Ukrainian authorities, 35 people were killed in the attack.