The Football Association has labelled Twitter attacks on England stars Ashley Young and Ashley Cole as "appalling and unacceptable''.
Cole and Young both missed penalties in Sunday night's quarter-final shootout against Italy as the Three Lions exited the tournament, and were subsequently subjected to abuse on Twitter.
"We are concerned at the reports regarding allegations of abuse aimed at England players Ashley Cole and Ashley Young on Twitter,'' an FA statement read.
"They have just given everything for the national team at Euro 2012 and it is appalling and unacceptable that messages of an abusive type are being posted. We support any police investigation in identifying who is behind this.''
A Metropolitan Police Service (MPS) spokesman said: "We are aware of alleged racist comments on Twitter following last night's England game and have launched an investigation.
"The allegation was made to MPS on 25 June by a member of the public relating to comments on a Twitter account supposedly based in London.
No arrests at this early stage. The MPS is examining possible offences under Section 18/19 Public Order Act 1986.''
The Twitter user in question made derogatory comments towards Young and Cole, but later wrote: "All I got to say is this was just a joke, you guys need to relax, police know i was kiddin around and they won't bother me hopefully, cheers.''
A Welsh student, Liam Stacey, was jailed for 56 days earlier this year for racially abusing Bolton midfielder Fabrice Muamba after he collapsed on the pitch against Tottenham Hotspur.