US ambassador to Nato Matthew Whitaker cast doubt on Tuesday on Russia’s accusation that Ukraine attacked President Vladimir ‌Putin’s residence, saying he wants to see US intelligence on the incident.

“It is ‍unclear whether it actually happened,” Whitaker told Fox Business’ Varney & Co chat show in an interview about an alleged incident which Ukraine has denied.

“It seems to me a little indelicate to be this close at a peace deal, Ukraine really ⁠wanting to get a peace deal done, and then to do something that would be viewed as reckless or not helpful,” he said.

Russia said on Monday that Ukraine had attacked a presidential residence in the Novgorod region with 91 long-range attack drones. It said it would retaliate and ‍that its negotiating stance would toughen in the talks.

Ukraine called Russia’s accusations “lies” aimed at justifying more attacks ‍on Ukraine and its foreign minister said on Tuesday that Russia had not provided any evidence “because there’s none”.

The Kremlin said on Tuesday it considered the alleged attack to be a “terrorist act” and a “personal attack against Putin”.