US officials said the drone attack on the Kremlin earlier this month was likely orchestrated by one of Ukraine’s special intelligence or military units, the latest in a series of covert actions against Russian targets that have baffled the Biden administration.

US intelligence agencies do not know which unit carried out the attack and it was not clear whether Ukraine’s President Volodymyr Zelensky or his senior officials were aware of the operation, although some officials believe Zelensky was not.

The agencies arrived at their preliminary assessment in part through intercepted communications in which Russian officials blamed Ukraine and other communications in which Ukrainian officials said they believed their country was responsible for the attack, in which two drones flew on May 3. May towards the Kremlin, causing little damage.

US officials say their level of confidence that the Ukrainian government directly authorized the drone attack on the Kremlin is “low,” but that’s because intelligence agencies do not yet have specific evidence identifying which government officials, units, or Ukrainian operatives were involved.

The attack appeared to be part of a series of operations that have angered officials in the United States, Ukraine’s biggest supplier of military equipment. The Biden administration is concerned about the risk that Russia will blame US officials and retaliate by expanding the war beyond Ukraine.

US spy agencies see an emerging image of a loose confederation of Ukrainian units capable of conducting limited operations inside and outside Russia, either using their own staff or partners working under their direction. Some of these missions could have been carried out with little or no oversight from Zelensky, the officials said.

In addition to the drone attack, US officials say they believe the Ukrainians were responsible for the murder of the daughter of a prominent Russian nationalist, the killing of a pro-Russian blogger and a series of attacks in Russian cities near the Ukrainian border. . the most recent of which occurred on Monday.

US officials also view the attack on the Nord Stream pipelines, which carried natural gas from Russia to Europe, as the work of pro-Ukrainian agents whose ties to the Ukrainian government have yet to be determined.

The officials, who spoke on condition of anonymity to discuss confidential intelligence, described their assessment in general terms but did not share details of the intercepts. Representatives for the White House, the Central Intelligence Agency and the Office of the Director of National Intelligence declined to comment.

Although the drone strike caused little damage, it pierced the sense of security and invincibility that the Kremlin has tried to portray inside Moscow despite the chaos it has created with its war in Ukraine.

The ability of US intelligence agencies to determine responsibility for attacks against Russian targets has been complicated by the way Ukraine has organized its security services, which have covert, overlapping, and sometimes conflicting responsibilities. opposite.

For example, the Ukrainian Security Service, the General Intelligence Directorate and the Ukrainian armed forces have their own special forces units.

They operate with varying levels of professionalism and oversight, and sometimes compete for resources and attention within the Ukrainian system. U.S. officials aren’t sure how closely, if at all, these units coordinate their activities with one another, either by design, as part of a compartmentalization system to prevent Russian moles from learning of their operations, or because mistrust between services. or both.

Some US officials initially considered the possibility that the Kremlin drone attack may have been carried out by the Russian government in a “false flag” operation designed to provide Moscow with a pretext to escalate the conflict.

But after the attack, the United States intercepted communications listening to Russian officials discuss the incident and the findings of Moscow’s preliminary investigation into what happened. In those internal discussions, Russian officials seemed surprised by the drone intrusion and blamed Ukraine. US officials said this intelligence helped convince them that the attack was not carried out by the Russians.

“Seeing how the Kremlin has responded suggests to me that this was an embarrassment and surprise to them, and not a deliberate false flag,” said Dara Massicot, a military analyst at RAND, referring to the drone strike. “The attacks also undermine perceptions of Moscow’s airspace surveillance capabilities and that the Kremlin is safe; these are important perceptions that they would like to maintain.”

The United States also intercepted Ukrainian conversations in which officials said they believed their country was responsible for the attack. But these officials appeared to have no knowledge of who within the Ukrainian establishment might have planned or carried it out.

US officials say some Ukrainian undercover agents work largely independently and without the direct supervision of Zelensky or his top deputies. Officials say they don’t think Mr. Zelensky condones all covert operations, and it’s unclear to what extent he knows about them in advance.

Instead, US officials said they suspect Zelensky and his top aides have set the broad parameters of the covert campaign, leaving decisions about who and what to target to the security services and their agents. By doing so, Mr. Zelensky and his top aides can deny knowing about them.

US officials have repeatedly warned Ukraine against carrying out high-profile attacks inside Russia, citing the risk of escalation. They have also generally dismissed the effectiveness of the attacks, which they see as a distraction from the more important fight: the Kiev campaign against Russian forces in southern and eastern Ukraine.

US officials have also publicly denied allowing or encouraging cross-border attacks and say they do not support the use of US equipment in such operations. The Biden administration does not want Moscow to think that the United States is complicit in the attacks.

The administration’s fears that Russia would use nuclear weapons or expand the conflict outside of Ukraine have subsided, at least for now, and the Ukrainians have continued to conduct covert operations on Russian soil despite US reservations.

While the covert attacks so far appear to have had little effect on the course of the conflict in Ukraine, they have demonstrated kyiv’s ability to penetrate deep into Russia. US officials say the aim of the operations may be to bolster Ukrainian morale and pierce the aura of invulnerability surrounding President Vladimir V. Putin.

Ukrainian military leaders have sometimes been reluctant to share information with the United States about war plans, worried that Russian or other spies would find out about them, making it difficult for Ukraine to surprise the enemy. The Ukrainians have been especially low-key about their covert operations.

The drone attack on the Kremlin took place in the early hours of May 3, several days before Russia celebrated Victory Day, which marked Russia’s victory over Nazi Germany in World War II.

The first drone started a small fire; the second drone exploded while two people were examining the roof for damage from the first, but did not appear to be injured. Russian authorities said the drones were intercepted and destroyed before they could cause any injuries.

A New York Times analysis of video of the attack showed the drones had a wingspan of about eight feet. US officials believe that the two drones involved were launched from a short distance, in or near Moscow. The drones, according to senior military officials, carried a limited explosive charge, suggesting that the detonations over the Kremlin were more on impact than any real threat.

Russian officials were quick to publicize the incident, saying it was an attempt by Ukraine to assassinate Putin. Russia has promised retaliatory measures and has been attacking Ukraine with regular missile barrages, though it is unclear whether the escalation came in direct response to the drone attack.

On the day of the drone attack, Mr. Zelensky publicly denied responsibility, stating that Ukraine is fighting on its own soil and keeping its weapons to defend Ukraine instead of attacking in Moscow. “We did not attack Putin,” he said.

A shadowy network of Russian partisan groups has claimed responsibility for several attacks, including the one on the Kremlin. But US intelligence agencies have found no evidence that such groups are responsible for the operations, and some US intelligence officials are skeptical that significant anti-Putin resistance forces are operating inside Russia.

christian triebert, Riley Mellen and michael schwirtz contributed reporting.