Abu Huthaifa al-Ansari was speaking in a recorded message posted on Thursday on the militant group’s Telegram channel.

Al-Ansari also reiterated urging the group’s supporters to target “crusaders” everywhere, especially in the US, Europe and Israel.

“We ask God that you make it to Palestine so you could fight the Jews face to face in an endless religious war,” he said.

Russian investigators said on Thursday they had found proof that the concert hall gunmen were linked to “Ukrainian nationalists”, an assertion immediately dismissed by the US as baseless propaganda.

Eleven people were arrested in the first 24 hours after the shooting and eight of them, including the four suspected gunmen, have been placed in pre-trial detention. Seven are from the Central Asian state of Tajikistan and the other from Kyrgyzstan.