An influential aide to Russian President Vladimir Putin said on Friday that the West and the US-led Nato alliance had helped to plan Ukraine’s surprise attack on Russia’s Kursk region, something Washington has denied.

The lightning incursion, the biggest into Russia by a foreign power since World War Two, unfurled on August 6 when thousands of Ukrainian troops crossed Russia’s western border in a major embarrassment for Putin’s military.

Ukraine said the incursion was needed to force Russia, which sent its forces into Ukraine in 2022, to start “fair” peace talks.

But the US and western powers, eager to avoid direct military confrontation with Russia, said Ukraine had not given advance notice and that Washington was not involved, though weaponry provided by Britain and the US is reported to have been used on Russian soil. Influential veteran Kremlin hawk Nikolai Patrushev dismissed the western assertions in an interview with the Izvestia newspaper.

“The operation in the Kursk region was also planned with the participation of Nato and Western special services,” he was quoted as saying, without offering evidence.

“Without their participation and direct support, Kyiv would not have ventured into Russian territory.” The remarks implied that Ukraine’s foray into Russian territory carried a risk of escalation.