wey kill over 90 pipo and injure 100 more, Russian security services tok.
At least four attackers wey wear camouflage cloth take part in di attack, in di north-west suburb of Krasnogorsk, BBC-verified video show.
Videos wey eye witness dem take show dramatic scenes from di attack.
Crocus City Hall bin wan host one rock concert wen di gunmen burst into di theatre.
Plenti of di building dey on fire and part of di roof collapse.
Pikin dem dey among di casualties and di Russian foreign ministry don condemn di “terrorist attack”.
According to one unverified statement online, militant group Islamic State tok say na dem dey behind di attack.
US officials tell CBS, di BBC partner service for US, say dem obtain intelligence wey show say IS bin wan to attack Russia. Di White House tok say e bin warn Russia earlier dis month of plan for potential attack for Moscow targeting “large gatherings”.
Russia National Guard tok say e get special units wey dey work for di scene to hunt down di attackers. Top Russian officials also dey go Krasnogorsk.
Two weeks ago, di US embassy put out warning to US citizens to avoid large gatherings, saying dem dey monitor reports say “extremists get plans to target large gatherings for Moscow”. Dem update dia advice on Friday evening, asking US citizens to avoid di area of di attack.
More dan 6,000 Russians bin go di Crocus City Hall retail and concert complex for one concert by rock group Picnic. One witness tok say di violence start minutes before di band come on stage. Picnic band members no dey harmed.
Russian President Vladimir Putin neva directly address di nation, but according to one of im deputies, im don wish those injured speedy recovery.
One security guard describe how di heavily-armed attackers burst into di foyer firing bullets as im alongside im colleagues dey work at di central entrance.
“Three odas security guards dey and dem hide behind one advertising board,” e tell Russian telegram channel Baza. “And those attackers pass 10m [30ft] away from us – dem start to dey shoot randomly at pipo on di ground floor.”
Inside di auditorium one woman tok say she and oda visitors rush towards di stage, as dem soon realise say shots dey fire. “I see pesin inside di stalls wit sidearm and cracks dey [of gunfire] going off, I dey try to crawl behind one loudspeaker,” she tell Russian TV.
Fire and smoke rise into di sky and di hall facade burst into fire as glass on di top two floors of di building blow out.
Di fire appear to don start wen di attackers throw some kind of device wey fit explode.
One man, Vitaly, describe say e see di attackers opening fire while e bin dey balcony inside di concert theatre: “Dem throw some petrol bombs, everitin start burning. Dem lead us out towards di exit.”
Anoda eyewitness say pikin dem and teenagers dey in di complex at di time of di attack, taking part in ballroom dancing competition.
While some of those inside di concert hall escape to di parking area from di stage, odas head to di roof and Russian authorities tok say about 100 more don escape through di basement.
Dem send dozens of ambulance crews immediately to di scene and e stand outside di complex in Krasnogorsk for some time afta di attack.
Moscow Mayor Sergei Sobyanin respond by cancelling all public events in di capital ova di weekend. “I dey sorry for di loved ones of di victims,” e tok.
In di following hours, several oda regions also cancel events, including Russia second biggest city St Petersburg.
Russian Foreign Ministry tok-tok pesin Maria Zakharova call on di international community to condemn di incident, e call am “monstrous crime”.
Ukraine goment dey quick to deny any involvement in di attack, wey come more dan two years afta Russia launch full-scale invasion on im neighbour.
“Regardless of everitin, for Ukraine, everitin go dey on di battlefield,” presidential adviser Mykhailo Podolyak tok on Telegram.
Only six days ago, Vladimir Putin win im fifth term for di Russian presidential elections. Di vote no include any genuine opponents and Western kontris denounce di elections as e no dey free or fair.
Ukrainian military intelligence tok-tok pesin Andriy Yusov suggest say di attack na “deliberate act of provocation by Putin special services”, without offering any evidence.
Friday night attack na di worst targeting civilians in Moscow for years, but e bring back memories of theatre siege inside di capital for 2002, wen 40 Chechen militants take more dan 900 pipo hostage during one musical wey dem dey call NordOst.
Russian security services eventually storm di theatre, pumping sleeping gas into di hall. Some 130 hostages die.
Security don tighten di airports and stations.
White House tok-tok pesin John Kirby tok say di the fotos of di shooting dey “horrible and hard to watch”.
“Our thoughts obviously dey wit di victims of dis terrible, terrible shooting attack,” im tok.
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