Armed police responded to a fight involving a knife outside the O2 Arena in Greenwich.
Four men were arrested following a “large” fight between two groups outside the venue just before 3am on Monday.
Scotland Yard said there were reports a firearm was also involved.
Met police and specialist firearms officers were called to reports of an altercation on Millennium Way.
They arrested four men on suspicion of grievous bodily harm and affray. The men remain in custody.
Three people were found on the scene suffering injuries including cuts and bruising.
MPS Firearms Command said on Twitter: “Officers from @MPSFirearms C Relief were called to support our unarmed @MPSGreenwich colleagues to detain a number of males involved in a large fight involving knives where people had been injured last night.
“Several arrests were made and this knife recovered.”
MORE ABOUT