NAIROBI, Kenya(CNN) -- [Breaking news 3:18 p.m. ET] Members of Al-Shabaab -- the militant group linked to al Qaeda that's claimed responsibility for Saturday's deadly mall attack in Kenya -- tweeted that "there will be no negotiations whatsoever" at the mall.
Al-Shabaab also tweeted Saturday that "all Muslims inside #Westgate" -- referring to the Kenyan mall that was attacked -- "were escorted out by the Mujahideen before" the violence began.
[Previously reported -- At least 30 killed in Nairobi mall attack; Islamic militants claim responsibility]
Police and gunmen were facing off Saturday night in an upscale shopping mall in the Kenyan capital after an attack that killed at least 30 people, authorities said.
Several hours after the assault began, Al-Shabaab, an al-Qaeda-linked militant group based in Somalia, claimed responsibility for the bloodshed.
"The Mujahideen entered #WestgateMall today at around noon and are still inside the mall," the Islamic extremist group said on its Twitter account.
But authorities said they had cornered the gunmen in the mall as of Saturday night.
"Attackers of Westgate shopping mall have been isolated and pinned down in a room by security forces in the ongoing operation," Kenyan police said on Twitter.
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