Iraqi officials and Syrian groups’ claims that Islamic State War Minister Omar al-Shishani has succumbed to his wounds from a March 5 airstrike have now been confirmed by American officials.

The spokesman for the U.S-led coalition told the Associated Press the Islamic State did not confirm Shishani’s death, but “the alliance was also confirming the militant commander had died.” Rami Abdurrahman, head of the Syrian Observatory for Human Rights, said Islamic State doctors could not save the terrorist.

Shishani passed away “in a hospital in the eastern suburbs of Raqqa.” An Iraqi commander said the Islamic State buried him in Deir el-Zour on Tuesday.

On Monday, Abdurrahmen said the injuries left Shishani “clinically dead.”

“Shishani is not able to breathe on his own and is using machines. He has been clinically dead for several days,” stated Rami Abdel Rahman, head of the Syrian Observatory for Human Rights.

Officials initially told Reuters the commander died in an airstrike on March 4 in al-Shaddadi. Another official said the U.S. targeted him specifically with the airstrike in question.

The following day, Rahman said Shishani had not yet died, but the terrorist group moved him to a hospital in Raqqa.

The United States placed Shishani, also known as Omar the Chechen, on its most-wanted militants list and offered a $5 million reward.

Shishani, born Tarkhan Batirashvili in Georgia, recruited others for jihad in his home country before he traveled to Syria and Iraq. Islamic State leader Abu Bakr al-Baghdadi promoted the red haired, fair-skinned Chechen to military chief. Unlike Baghdadi, Shishani made many public appearances. He appeared prominently in a propaganda video touring a children’s terrorist training camp.

Outside of the Middle East, Russia is the largest contributor of people to ISIS. Last summer, Russian Foreign Minister Oleg Syromolotov announced that over 2,200 Russians are currently fighting with the Islamic State (ISIS/ISIL/IS) terrorist group.

“The figures start getting really alarming,” he stated, adding:

At the time being, around 2,200 people from Russia are engaged in the fighting in Syria and Iraq. Among them, about 500 came from Europe, where they had earlier obtained citizenship, residence permit or refugee status. We are thoroughly analyzing belligerent statements of IS leaders on transition of the “jihad” to Northern Caucasus and in Central Asia.

Syromolotov also said the number is alarming because so many people could possibly come back radicalized.

“It’s clear that they bring along not only their terrorist potential itself, but also radical ideas, a source for negative ideological impact on the society, especially on its most vulnerable members,” he said.

In mid-June, the Interior Ministry reported over 400 Chechens have joined terrorist groups, mainly ISIS, since the Syrian Civil War broke out.

“A total of 405 people, according to our data, have left Chechnya to join the fighting in Syria on the side of the Islamic State since the beginning of the war in that region,” said the spokesman. “Among those, 104 have been killed and 44 came back, while the fate of the rest is unknown.”

Chechens in Syria have threatened President Vladimir Putin for supporting Syrian President Bashar al-Assad, and in a video released last September, vowed to liberate Chechnya and Russia’s North Caucasus.

“We will, with the consent of Allah, free Chechnya and all of the Caucasus!” said the fighter. “The Islamic State is here and will stay here, and it will spread with the grace of Allah! Your throne has already been shaken. It is under threat and will fall with our arrival. We’re already on our way with the grace of Allah!”