Britain's Amir Khan took to Twitter on Thursday as he stepped up his complaints over his world title defeat by Lamont Peterson in Washington last month.

He told his followers on the social networking site he was particularly concerned by the presence of an unknown man in a hat at ringside, who he claimed was talking to bout supervisor Michael Walsh, in contravention of a rule that states no one should speak to officials while a fight is in progress.

Khan lost his International Boxing Federation (IBF) and World Boxing Association (WBA) titles to Peterson in a close points decision, with referee Joe Cooper taking two points away from Khan for pushing.

Without that deduction, Khan would have kept his titles and there was further controversy over the unusually long delay that ensued between the final bell and the announcement of the judges' scorecards.

Khan's appeal against his defeat is due to be heard later this month.

In the meantime the 26-year-old took expressed his latest concerns with a series of tweets and links to video footage of the fight.

"Sat on the main judges panel at the front on the right hand side, third to the end… From round six all the way through to round twelve this guy starts to interfere with what Michael Walsh is doing and they are both not watching the fight, watch the video and have a look for yourselves," Khan posted.

"No one is allowed, according to the rules, to touch hold the scorescards or even talk to the judges on commission during the fight.

"There are three judges in a fight and all have different color slips, and at the end of every round they get passed on to the WBA, IBF and DC commission.

"This pic shows here in round six the guy wearing the hat [clearly picking] up one of the judges white slips and if you watch the video [he] slides it down and towards him."

Khan added: "Again in round eight and round nine, cleary not watching the fight at all and not allowing Michael Walsh to watch too.

"This time in round eleven he's seen here clearly picking up a yellow judges slip.. Strictly againts the rules.

"I want Michael Walsh to come out and speak out about what was going on, it's only right and fair to do so.

"The question is.. Who is this guy? And what was he doing? I'm sure someone out there knows."