Al-Shishani, born Tarkhan Batirashvili, is among the most recognizable members of the so-called Islamic State's leadership. The ethnic Chechen is from Georgia's Pankisi Valley, which was once considered a stronghold for militants.
“Tarkhan Batirashvili, the enemy of Islam who called himself Omar al-Shishani, has been killed.
[The same fate belies] anyone who even thinks about threatening Russia and the Chechen people,” Kadyrov wrote on Instagram alongside a photograph of the supposedly dead militant.
In a videotaped address to Russian President Vladimir Putin posted on the Internet in September, ISIS members threatened to wage war on the North Caucasus, a predominantly Muslim region that for years battled an insurgency led by Islamic fundamentalists.
"We will, with the consent of Allah, free Chechnya and all of the Caucasus! The Islamic State is here and will stay here, and it will spread with the grace of Allah," militants said in the video.
Kadyrov dismissed the threat at the time, saying it was nothing more than a “childish threat.”
On Oct. 9, Bloomberg reported that al-Shishani called his father to say he would have “revenge” on President Vladimir Putin. His father, Temur Batirashvili, told Bloomberg that al-Shishani said, “Don’t worry, Dad, I’ll come home and show the Russians.”
A video in August showing a person calling himself Omar al-Shishani, and claiming to be commander of one of the largest groups of ISIS soldiers in Syria, threatened to come with his troops to the Caucasus and stage attacks against Russians. Kadyrov, who is close to Putin and a supporter of President Bashar al-Assad’s government in Syria, responded that al-Shishani will never make it to Russia, and if he does, he will be “liquidated” there.
This is not the first time Kadyrov has been the first source of official information on the death of an Islamic terrorist, but it is a subject he has been wrong about in the past.
In January, ahead of the Winter Olympics in Sochi, Kadyrov announced that Doku Umarov, widely considered Russia's enemy No. 1 in its battle with the Islamic insurgency in the North Caucasus, had been killed.
But that declaration came after many more just like it, with Kadyrov repeatedly proclaiming Umarov dead only to have him pop up again in threatening video addresses.
Russia's Federal Security Service confirmed Umarov's death in April, two months after the Olympics.