United States intelligence agencies believe this month’s drone strike against the Kremlin was likely orchestrated by Ukrainian spies or Ukrainian military intelligence, the New York Times reports.

The newspaper said the attack appeared to be part of a series of covert operations that have embarrassed officials in the United States, which is Ukraine’s biggest supplier of military equipment.

The US estimate is based on intercepted Russian and Ukrainian communications, the New York Times reports.

The United States intercepted Ukrainian conversations in which officials said they believed their country was responsible for the attack, and also intercepted Russian communications that showed it was not a deception operation by Russia, they added.

“We immediately said that the Kiev regime was behind it,” Kremlin spokesman Dmitry Peskov said when asked about the report.

“Ultimately it doesn’t make much difference which of the units of the Kiev regime was behind it. The Kiev regime was behind it, we know that, we know that, and we will proceed on that basis,” he added.

US officials said they do not believe Ukrainian President Volodymyr Zelensky approves all covert operations, the newspaper reported. It is unclear to what extent he has prior knowledge of these operations, officials are quoted as saying.

Russia accused Ukraine of trying to kill Russian President Vladimir Putin with the attack. Zelensky immediately denied any Ukrainian involvement.

The Kremlin has also claimed the United States was behind the drone strike, a view Washington has dismissed as ludicrous.