[[Negara Islam –Irak Provinsidan Syam Khorasan]] (IS-KP) mengaku bertanggung jawab atas serangan tersebut dalam pernyataan [[:en:Amaq News Agency|Kantor Berita Amaq]],<ref name=":3" /><ref>{{Cite web |date=22 March 2024 |editor-last=Wertheimer |editor-first=Tiffany |title=Report: Islamic State claims responsibility |url=https://www.bbc.com/news/live/world-68642036?ns_mchannel=social&ns_source=twitter&ns_campaign=bbc_live&ns_linkname=65fdfa3fb26acd1fbf32f812%26Report%3A%20Islamic%20State%20claims%20responsibility%262024-03-22T21%3A41%3A57.713Z&ns_fee=0&pinned_post_locator=urn:asset:f4bef7a3-a4b2-442a-9c48-27d6f3e8d27e&pinned_post_asset_id=65fdfa3fb26acd1fbf32f812&pinned_post_type=share |url-status=live |archive-url=https://web.archive.org/web/20240323024104/https://www.bbc.com/news/live/world-68642036?ns_mchannel=social&ns_source=twitter&ns_campaign=bbc_live&ns_linkname=65fdfa3fb26acd1fbf32f812%26Report%3A%20Islamic%20State%20claims%20responsibility%262024-03-22T21%3A41%3A57.713Z&ns_fee=0&pinned_post_locator=urn:asset:f4bef7a3-a4b2-442a-9c48-27d6f3e8d27e&pinned_post_asset_id=65fdfa3fb26acd1fbf32f812&pinned_post_type=share |archive-date=23 March 2024 |access-date=22 March 2024 |website=[[BBC News]] |language=en-gb }}</ref> yang mengatakan bahwa para penyerang "mundur ke markas mereka dengan selamat".<ref>{{Cite news |date=23 March 2024 |title=Islamic State Group Claims Russia Gun Attack |url=https://www.themoscowtimes.com/2024/03/23/islamic-state-group-claims-russia-gun-attack-a84583 |access-date=2024-03-23 |work=[[The Moscow Times]] |language=en-GB |archive-date=22 March 2024 |archive-url=https://web.archive.org/web/20240322220910/https://www.themoscowtimes.com/2024/03/23/islamic-state-group-claims-russia-gun-attack-a84583 |url-status=live }}</ref> Kelompok ini merupakan cabang regional dari [[Negara Islam Irak dan Syam|ISIS]], sebuah kelompok teroris internasional yang aktif di [[Asia Selatan]]-[[Asia Tengah|Tengah]], terutama [[Afganistan|Afghanistan]] dan [[Pakistan]].<ref>{{Cite news |last=Gardner |first=Frank |date=2021-08-26 |title=Afghanistan: Who are Islamic State Khorasan Province militants? |url=https://www.bbc.com/news/world-asia-58333533 |url-status=live |archive-url=https://archive.today/20210828204435/https://www.bbc.com/news/world-asia-58333533 |archive-date=28 August 2021 |access-date=2024-03-23 |work=[[BBC News]] |language=en-GB}}</ref> Para pejabat AS menyatakan mereka memiliki informasi intelijen yang menunjukkan bahwa IS-KP telah merencanakan serangan terhadap kota tersebut.<ref name="U.S. confirmation">{{Cite news |last1=Barnes |first1=Julian E. |last2=Schmitt |first2=Eric |date=22 March 2024 |title=U.S. Says ISIS Was Responsible for Deadly Moscow Concert Hall Attack |url=https://www.nytimes.com/2024/03/22/world/europe/isis-moscow-attack-concert-hall.html |url-access=subscription |url-status=live |archive-url=https://web.archive.org/web/20240322225756/https://www.nytimes.com/2024/03/22/world/europe/isis-moscow-attack-concert-hall.html |archive-date=22 March 2024 |access-date=22 March 2024 |work=[[The New York Times]]}}</ref> Surat kabar Rusia ''[[:ru:Коммерсантъ|Kommersant]]'' melaporkan dari sumber bahwa [[:en:Russian Volunteer Corps|Korps Relawan Rusia]] dicurigai, dan pelakunya digambarkan sebagai "pemuda, [[orang Slavia]], tinggi badan di atas rata-rata, dan kemungkinan menggunakan janggut dan kumis palsu".<ref>{{Cite web |date=2024-03-22 |title=Terrorist attack at concert hall outside Moscow |url=https://meduza.io/en/live/2024/03/22/terrorist-attack-at-concert-hall-outside-moscow |access-date=2024-03-22 |website=meduza.io |archive-date=22 March 2024 |archive-url=https://web.archive.org/web/20240322192311/https://meduza.io/en/live/2024/03/22/terrorist-attack-at-concert-hall-outside-moscow |url-status=live }}</ref> Baik RVC[[:en:Russian Volunteer Corps|Korps Relawan Rusia]] maupun kelompok militan anti-Kremlin lainnya, [[:en:Russian Legion of Freedom|Legiun Kebebasan Rusia]], membantah terlibat dalam serangan tersebut.<ref name="novayagazeta">{{Cite web |date=2024-03-23 |title=At least 40 killed in shooting at Moscow concert hall |url=https://novayagazeta.eu/articles/2024/03/22/at-least-12-reportedly-killed-in-shooting-at-moscow-concert-hall-en-news |access-date=2024-03-23 |website=Novaya Gazeta }}</ref>
[[:en:Mykhailo Podolyak|Mykhailo Podolyak]], penasihat presiden Ukraina [[Volodymyr Zelenskyy]], menulis bahwa [[Ukraina]], yang saat ini sedang [[Invasi Rusia ke Ukraina 2022|berperang dengan Rusia]], tidak terlibat dalam serangan tersebut.<ref>{{cite news |last=Yang |first=Maya |date=22 March 2024 |title=Ukraine denies involvement in attacks |url=https://www.theguardian.com/world/live/2024/mar/22/moscow-concert-attack-crocus-city-hall-shooting-russia-live-updates?CMP=share_btn_url&page=with%3Ablock-65fde08a8f08214a64619c22#block-65fde08a8f08214a64619c22 |url-status=live |archive-url=https://web.archive.org/web/20240323004353/https://www.theguardian.com/world/live/2024/mar/22/moscow-concert-attack-crocus-city-hall-shooting-russia-live-updates?CMP=share_btn_url&page=with%3Ablock-65fde08a8f08214a64619c22#block-65fde08a8f08214a64619c22 |archive-date=23 March 2024 |access-date=22 March 2024 |work=[[the Guardian]] |issn=0261-3077 }}</ref> [[Gedung Putih]] menyebut situasi ini "mengerikan" dan mengatakan tidak ada indikasi keterlibatan Ukraina dalam serangan tersebut.<ref>{{cite web |date=22 March 2024 |title=Russia Concert Hall Attack 'Terrible': White House |url=https://www.barrons.com/news/russia-concert-hall-attack-terrible-white-house-fea2f3dc?refsec=topics_afp-news |url-status=live |archive-url=https://web.archive.org/web/20240322192717/https://www.barrons.com/news/russia-concert-hall-attack-terrible-white-house-fea2f3dc?refsec=topics_afp-news |archive-date=22 March 2024 |access-date=22 March 2024 |website=[[Barron's]] |agency=[[Agence France Presse]]}}</ref>
Hingga tanggal 23 Maret, masing-masing pelaku belum teridentifikasi.<ref name=":6" />
