Shoppers and other travellers ran away as the man roamed the streets for up to 15 minutes.
A man stabbed a passenger on a train at a south London station and then chased people shouting: "I want to kill a Muslim", the Daily Mirror reported on Monday, in an incident police said was not "terrorism-related."
Shoppers and other travellers ran away as the man roamed the streets for up to 15 minutes, the newspaper reported.
"A man has been arrested after a man was seriously assaulted at Forest Hill station this afternoon," British Transport Police said in a statement on their website.
"We are investigating the circumstances of the Forest Hill incident, but at this time we are not treating it as terrorism-related."
© Thomson Reuters 2016