By Julian E. Barnes, Adam Goldman, Adam Entous and Michael Schwirtz

WASHINGTON — US intelligence agencies believe parts of the Ukrainian government authorized the car bomb attack near Moscow in August that killed Daria Dugina, daughter of a prominent Russian nationalist, an element of a covert campaign that US officials fear could widen the conflict.

The United States took no part in the attack, either by providing intelligence or other assistance, officials said. US officials also said they were not aware of the operation ahead of time and would have opposed the killing had they been consulted. Afterward, US officials admonished Ukrainian officials over the assassination, they said.

The closely held assessment of Ukrainian complicity, which has not been previously reported, was shared within the US government last week. Ukraine denied involvement in the killing immediately after the attack, and senior officials repeated those denials when asked about the US intelligence assessment.

While Russia has not retaliated in a specific way for the assassination, the United States is concerned that such attacks — while high in symbolic value — have little direct effect on the battlefield and could provoke Moscow to carry out its own strikes against senior Ukrainian officials. US officials have been frustrated with Ukraine’s lack of transparency about its military and covert plans, especially on Russian soil.

Since the beginning of the war, Ukraine’s security services have demonstrated their ability to reach into Russia to conduct sabotage operations. The killing of Dugina, however, would be one of the boldest operations to date — showing Ukraine can get very close to prominent Russians.

Some US officials suspect Dugina’s father, Alexander Dugin, a Russian ultranationalist, was the actual target of the operation and that the operatives who carried it out believed he would be in the vehicle with his daughter.

Dugin, one of Russia’s most prominent voices urging Moscow to intensify its war on Ukraine, has been a leading proponent of an aggressive, imperialist Russia.

The US officials who spoke about the intelligence did not disclose which elements of the Ukrainian government were believed to have authorized the mission, who carried out the attack or whether President Volodymyr Zelenskyy had signed off on the mission. US officials briefed on the Ukrainian action and the American response spoke on the condition of anonymity, in order to discuss secret information and matters of sensitive diplomacy.

US officials would not say who in the American government delivered the admonishments or whom in the Ukrainian government they were delivered to. It was not known what Ukraine’s response was.

While the Pentagon and spy agencies have shared sensitive battlefield intelligence with the Ukrainians, helping them zero in on Russian command posts, supply lines and other key targets, the Ukrainians have not always told US officials what they plan to do.

The United States has pressed Ukraine to share more about its war plans, with mixed success. Earlier in the war, US officials acknowledged that they often knew more about Russian war plans — thanks to their intense collection efforts — than they did about Kyiv’s intentions.

Cooperation has since increased. During the summer, Ukraine shared its plans for its September military counteroffensive with the United States and Britain.

US officials also lack a complete picture of the competing power centres within the Ukrainian government, including the military, the security services and Zelenskyy’s office, a fact that may explain why some parts of the Ukrainian government may not have been aware of the plot.

When asked about the US intelligence assessment, Mykhailo Podolyak, an adviser to Ukraine’s president, reiterated the Ukrainian government’s denials of involvement in Dugina’s killing.

“Again, I’ll underline that any murder during wartime in some country or another must carry with it some kind of practical significance,” Podolyak told The New York Times in an interview Tuesday. “It should fulfil some specific purpose, tactical or strategic. Someone like Dugina is not a tactical or a strategic target for Ukraine.

“We have other targets on the territory of Ukraine,” he said. “I mean collaborationists and representatives of the Russian command, who might have value for members of our special services working in this program, but certainly not Dugina.”

Though details surrounding acts of sabotage in Russian-controlled territory have been shrouded in mystery, the Ukrainian government has quietly acknowledged killing Russian officials in Ukraine and sabotaging Russian arms factories and weapons depots.

A senior Ukrainian military official who declined to be identified because of the sensitivity of the topic said that Ukrainian forces, with the help of local fighters, had carried out assassinations and attacks on accused Ukrainian collaborators and Russian officials in occupied Ukrainian territories. These include the Kremlin-installed head of the Kherson region, who was poisoned in August and had to be evacuated to Moscow for emergency treatment.

Countries traditionally do not discuss other nations’ covert actions, for fear of having their own operations revealed, but some US officials believe it is crucial to curb what they see as dangerous adventurism, particularly political assassinations.

Still, US officials in recent days have taken pains to insist that relations between the two governments remain strong. US concerns about Ukraine’s aggressive covert operations inside Russia have not prompted any known changes in the provision of intelligence, military and diplomatic support to Zelenskyy’s government or to Ukraine’s security services.

In a phone call Saturday (Oct 1), Secretary of State Antony Blinken told his Ukrainian counterpart, Dmytro Kuleba, that the Biden administration “will continue to support Ukraine’s efforts to regain control of its territory by strengthening its hand militarily and diplomatically,” according to Ned Price, the State Department’s spokesperson.

Officials from the State Department, National Security Council, Defence Department and CIA declined to comment on the intelligence assessment.

The war in Ukraine is at an especially dangerous moment. The United States has tried carefully to avoid unnecessary escalation with Moscow throughout the conflict — in part by telling Kyiv not to use American equipment or intelligence to conduct attacks inside of Russia. But now, the recent battlefield successes by Ukraine have prompted Russia to respond with a series of escalatory steps, like conducting a partial mobilization and moving to annex swathes of eastern Ukraine.

Concern is growing in Washington that Russia may be considering further steps to intensify the war, including by renewing efforts to assassinate prominent Ukrainian leaders. Zelenskyy would be the top target of Russian assassination teams, as he was during the Russian assault on Kyiv earlier in the war.

But now, US officials said Russia could target a wide variety of Ukrainian leaders, many of whom have less protection than Zelenskyy.

The United States and Europe had imposed sanctions on Dugina. She shared her father’s worldview and was accused by the West of spreading Russian propaganda about Ukraine.

Russia opened a murder investigation after Dugina’s assassination, calling the explosion that killed her a terrorist act. Dugina was killed instantly in the explosion, which occurred in the Odintsovo district, an affluent area in Moscow’s suburbs.

After the bombing, speculation centred on whether Ukraine was responsible or if it was a false flag operation meant to pin blame on Ukrainians. The bombing took place after a series of Ukrainian strikes in Crimea, a part of Ukraine that Russia seized in 2014. Those strikes had led ultranationalists in Dugin’s circle to urge Putin to intensify the war in Ukraine.

Russia’s domestic intelligence service, the FSB, blamed Dugina’s murder on Ukraine’s intelligence services. In an announcement made a day after the attack, the FSB said that Ukrainian operatives had contracted a Ukrainian woman, who entered Russia in July and rented an apartment where Dugina lived. The woman then fled Russia after the bombing, according to the FSB.

Ilya Ponomarev, a former member of the Russian parliament who voted against the annexation of Crimea, has claimed that a group made up of pro-Ukrainian and anti-Putin fighters operating in Russia known as the National Republican Army was responsible for the killing.

In an interview with The New York Times, Ponomarev claimed to be in contact with the National Republican Army and was aware of the operation against Dugina several hours before it occurred. Many officials in Washington have been sceptical of Ponomarev’s claims on behalf of the group.

-New York Times