Police had earlier said they were responding to reports of shots fired as if they could be terrorist-related.
"To date police have not located any trace of any suspects, evidence of shots fired or casualties," the Metropolitan Police said in a statement.
"If you are in building stay in a building, if you are on the street in Oxford Street leave the area," they added.

"Oxford Circus and Bond Street stations now both reopened and all trains are stopping normally," the transport authority said on one of its official Twitter accounts.
Police have said there is no evidence that shots had been fired or that there were any serious casualties.
© Thomson Reuters 2017