Still from the video on  Kadyrov's Istagrampage
Still from the video on Kadyrov's Istagram page showing the opposition activists Mikhail Kasyanov and Vladimir Kara-Murza targetted by an assassin's rifle Instagram

A Russian opposition leader says he has been told by security services that a video posted online showing him targeted by rifle crosshairs broke no laws.

The video was posted on the Instagram page of Chechen leader Ramzan Kadyrov on 1 February, and shows opposition Parnas party leader Mikhail Kasyanov and opposition activist Vladimir Kara-Murza in the crosshairs of a sniper's rifle, with the message "Those who didn't understand, will."

Kasyanov, a former deputy prime minister who has since become a vocal critic of the Kremlin, said in a posting on his Facebook page the FSB response "means that the head of the security services and all other law enforcement agencies, Russian President Vladimir Putin, approves of these methods of political struggle against me and the Parnas democratic coalition".

Shortly after the video was posted, Kasyanov and colleagues were verbally abused and attacked with food by a group of men in a Moscow restaurant, in an incident Kasyanov claimed was a clear attempt to intimidate him and other Kremlin critics.

In a recent report, Kasyanov's party colleague Ilya Yashin branded Kadyrov, who was handpicked by Russian President Vladimir Putin, a security threat. Kadyrov has in recent weeks indicated he would be willing to relinquish power, prompting fawning pleas from supporters on social media for him to remain in power.

In the wake of the murder of Russian opposition leader Boris Nemtsov in Moscow last February, Kadyrov praised the suspected assassin, former Chechen security forces member Zaur Dadayev. Shortly after, Putin awarded Kadyrov a state honour.

The European Union, human rights groups, and opposition activists called on Russian authorities to investigate the video. The FSB response read: "The post contains no attributes of any illegal actions," said Kasyanov in the Facebook post.