A Scotland Yard statement said:
"Police attended an address in Albert Square to execute an arrest warrant at approximately 9am... While officers from Newham attempted to arrest a male suspect, they were attacked by a pit bull-type dog.
"A dog unit was called to the scene and CO19 Specialist Firearms Command also attended. The dog was contained and subsequently shot dead."
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The victims were collecting permits and escorts a day after their home town was liberated from the extremists.