Ukraine has denied being responsible for two drones Russia says it shot down as they approached the Kremlin.

Moscow claimed on Wednesday that an assassination attempt had taken place on president Vladimir Putin, though he was not in the building at the time.

Russia called the incident "a planned terrorist act and an assassination attempt on the president".

The Ukrainian government did not immediately comment, but president Volodymyr Zelenskyy's official spokesperson officially denied responsibility and said that Ukraine was focused on liberating its own territory.

Read More: Russia accuses Ukraine of trying to kill Vladimir Putin

The Kyiv government said: "We have no information about the so-called night attacks on the Kremlin but as President Zelenskyy has repeatedly stated, Ukraine directs all its available forces and means toward the liberation of its own territories, not to the attack of others."

Advisor Mykhailo Podolyak expanded on that, writing on Twitter: "As for the drones over the Kremlin, it’s all predictable... Russia is clearly preparing a large-scale terrorist attack. That's why it first detains a large allegedly subversive group in Crimea. And then it demonstrates 'drones over the Kremlin'.

"First of all, Ukraine wages an exclusively defensive war and does not attack targets on the territory of the Russian Federation. What for? This does not solve any military issue. But it gives RF grounds to justify its attacks on civilians... Secondly, we are watching with interest the growing number of mishaps and incidents that are taking place in different parts of RF.

"The emergence of unidentified unmanned aerial vehicles at energy facilities or on Kremlin’s territory can only indicate the guerilla activities of local resistance forces. As you know, drones can be bought at any military store... The loss of power control over the country by Putin’s clan is obvious.

"But on the other hand, Russia has repeatedly talked about its total control over the air. In a word, something is happening in RF, but definitely without Ukraine's drones over the Kremlin..."

Some have suggested a potential 'false flag' attack to justify escalation in Ukraine, though others have pointed out that allowing a drone to get within striking distance of the Kremlin is unlikely to be a propaganda win for Mr Putin.

In its statement on the incident, Moscow said: "Russia reserves the right to take countermeasures wherever and whenever it deems appropriate".