Latest on investigation

into Manchester concert bombing: ISIS issued its claim of responsibility
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LONDON -- CBS News confirmed Tuesday that the man who blew himself up the previous night at an Ariana Grande concert in Manchester, England, was 23-year-old Salman Abedi, who was known to British authorities prior to the attack.

In a generic statement posted online, the Islamic State of Iraq and Syria (ISIS) claimed responsibility for Abedi's suicide bomb attack, which left 22 people dead, including children, at one of the entrances to the Manchester Arena.

Morell says U.K. bomber was "conscious of how to maximize casualties"

Officials said one man was arrested Tuesday in southern Manchester in connection with the attack, and urged people to avoid the center of the city as operations continued. Police and British Prime Minister Theresa May made it clear the focus of the investigation was to determine whether the bomber "was acting alone, or was part of a wider group."

ISIS issued its claim of responsibility in a brief, generic statement that did not identify the bomber and appeared to get some of the facts of the attack wrong. It claimed a "caliphate soldier managed to place a number of devices among a gathering of crusaders in Manchester, and detonated them."

Officials say there was only one explosion, and there have been no indications that other devices were discovered(how well were they hid and when will they go off?) at or near the arena.

U.S. intelligence sources told CBS News they were exercising caution on the early claim of responsibility from ISIS. Authorities are still looking into whether it was a killer who acted alone or who might have had some level of support from the terror network. U.S. intelligence officials were offering assistance in the investigation, as is standard practice in any case involving a close ally.

ISIS has repeatedly called for its supporters in the West to attack "soft targets" like sports events and concerts in any way possible.