(NewsNation) — Russia claimed Wednesday that it foiled a Ukrainian drone attack on the Kremlin. If that is indeed true, it was an embarrassing show of weakness, according to one military expert.

Moscow called it an unsuccessful assassination attempt against President Vladimir Putin and promised retaliation for what it termed a “terrorist” act. Ukraine denied the allegation.

Putin wasn’t in the Kremlin at the time; he was at his Novo-Ogaryovo residence outside Moscow, his spokesman Dmitry Peskov told Russia’s state news agency RIA Novosti.

Retired Lt. Col. Alexander Vindman, former director of European Affairs for the National Security Council, said Wednesday on “CUOMO” that the strike was clearly not an assassination attempt.

“Ukrainians know the pattern of life for Vladimir Putin. They know that he actually doesn’t spend his time at the Kremlin,” Vindman said. “What seems to be more likely is that this was a symbolic strike against the Kremlin … right before the Victory Day.”

That holiday, held annually May 9, commemorates the Soviet Union’s victory over Nazi Germany in 1945.

The celebrations usually include shows of military might, but celebrations for this year have been scaled back, the BBC reported.

“The fact that you have drones flying over the Kremlin and being shot down … that’s not a demonstration of power, that’s a demonstration of weakness,” Vindman said.

Echoing Vindman, retired Lt. Gen. Richard Newton said on “Elizabeth Vargas Reports” that the thwarted drone attack shows a “lapse in Russian security around perhaps their most coveted point of reference in Moscow.”

There was no independent verification of the purported attack, which Russian authorities said occurred overnight but presented no evidence to support it. Questions also arose as to why it took the Kremlin hours to report the incident and why videos of it also surfaced later in the day.

A video posted overnight on a local Moscow news Telegram channel, shot from across the river from the Kremlin, appeared to show smoke rising over the buildings. It wasn’t possible to ascertain its veracity. According to text accompanying the footage, residents of a nearby apartment building reported hearing bangs and seeing smoke around 2:30 a.m.

Another video on social media, which looks to be taken from across Red Square, appears to show the moment a drone explodes in a flash of fire above the roof of the Senate Palace in the Kremlin, near a flagpole flying the Russian tricolor, with debris falling on the roof. It also was not possible to independently verify this footage.

The Kremlin said Russian military and security forces had stopped the drones before they could strike. Nobody was hurt, it added. Its official website said debris from the drones fell on the Kremlin grounds without damage.

Before the news about the alleged attack broke, Moscow Mayor Sergei Sobyanin issued a ban on using drones in the Russian capital, with an exception for those launched by authorities. He gave no reason for the ban, saying only it would prevent the “illegal use of drones that can hinder the work of law enforcement.”

Based on the size of the drones, Newton suggested they would have had to have been controlled within close range.

“Whoever launched these drones had to be nearby,” Newton said. “It certainly wouldn’t be 300 or 400 miles (away in) Kyiv.”

Russia vowed to retaliate, which Vindman believes is unlikely.

“Where does Russia go with this? Does Russia use this to rally tens of thousand troops, another mobilization? They didn’t need a pretext for this,” Vindman said. “It doesn’t make a lot of sense from a false-flag perspective.”

Instead, he suggested the likeliest explanation is a pro-Ukrainian militant group that was able to get past Russian defenses.

“They’ve been trying to do this for months. There have been other attempts that haven’t been successful and they finally made it to the target,” Vindman said. “It’s quite embarrassing for Russia that they have to contend with this.”

The Associated Press contributed to this report.