Cops were called to Argyle Square, Bloomsbury just after 1.30pm this afternoon after reports of an altercation between two groups of males.
Scotland Yard said the groups had left the location before officers arrived at the scene.
Two men were later found nearby with facial injuries reported to have been caused by a corrosive substance.
They have been taken to a nearby hospital.
Their condition is not yet known and no arrests have been made.
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