West Ham co-chairmen David Sullivan and David Gold have complained of being targeted for abuse by Leicester supporters in Sunday's draw at the Walkers Stadium.
The 2-2 result came as a blow to Leicester's Barclays Premier League title ambitions, with only a late penalty from Leonardo Ulloa sparing the Foxes from defeat.
Leicester led through Jamie Vardy's goal, but the striker was later sent off and Andy Carroll's penalty drew the teams level before Aaron Cresswell fired West Ham ahead. Carroll's challenge on Jeff Schlupp was punished with the stoppage-time penalty from which Leicester forced the draw.
Sullivan told the Daily Mirror: "We didn't stay to applaud our own players off as we felt threatened. We've spoken to Leicester and they've told us they would look into it."
Gold wrote on Twitter: "Elderly Leicester fans turned into monsters when WHU went 2-1 up then returned to nice old people when LCFC equalised."
He added on Tuesday: "I want Leicester to win the PL and I am pleased for their fans but their behaviour towards us was unacceptable."
Slaven Bilic admits Leicester's "fairytale" season has put West Ham's success in the shade.
The Hammers are still fighting for a top-four finish and a place in the Champions League with six games remaining.
But on Sunday they head to the King Power Stadium to take on a Foxes side on the verge of an incredible Premier League title, just a year after looking like certainties for relegation.
"People recognise we are having a good season, we are playing good football, and they are praising us," said Hammers boss Bilic.
"But what Leicester have done puts our successful season a little bit in the shadows.
"That's normal. It's like a fairytale and they deserve all the credit they are getting. It is unbelievable."
Leicester-based referee Kevin Friend has been switched from taking charge of Tottenham's Barclays Premier League match at Stoke on Monday night.
The Professional Game Match Officials Limited said the change was made to avoid adding an "extra scrutiny on the refereeing appointment" around Friend, who lives in Leicester and has been to games at the King Power Stadium.
Leicester lead the table by seven points ahead of Spurs with five matches remaining.
While there is no suggestion of any question over the official's integrity in his impartial position, the PGMOL, which does not select Friend for matches involving his hometown club, felt given the circumstances it was sensible to move him to another fixture.
A statement read: "PGMOL has made the decision to change the referee for the match between Stoke City and Tottenham Hotspur as Kevin Friend, initially selected for the game, is from Leicester and has attended matches at Leicester City in a personal capacity.
"Given the timing and context of this match, it was felt unnecessary to add extra scrutiny on the refereeing appointment.
"Neil Swarbrick will referee the match and Friend will referee Newcastle United vs Manchester City."
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Leicester forward Riyad Mahrez has insisted the team are under no pressure as they chase a first top-flight title in the club's 132-year history.
The Algeria international had not expected at the start of the season that, with nine games to go, the Foxes would be looking down from the top of the Barclays Premier League, with a five-point advantage over the following pack.
As he nears the end of a remarkable season - which has seen him score 15 league goals and be strongly tipped to be crowned PFA Player of the Year - he brushed off suggestions that he was looking ahead to a possible transfer to a bigger club.
"I'm not thinking about that," he said. "The last games we need to keep working hard and see what we can do. I'm really not thinking about this. I have three more years in Leicester and then we'll see."
But he did admit he did not start the 2015/16 campaign anticipating Leicester would be top of the table in March.
"I wasn't expecting that, but that's now the reality," he said. "I'm happy to be here. I'm pleased."
Asked whether he was feeling the pressure, he replied: "No pressure. We are playing as always. We will just see what can happen for us.
"We just work hard for everyone. We are just a good team, good team-mates and we are doing well. We have to keep going."
There has been an increase in the number of flu cases in February in the Leicester area according to the lead nurse for infection prevention at Leicester's hospitals.
Three wards at Leicester Royal Infirmary have been closed after a swine flu outbreak affected 14 cancer patients.
We have seen an increase in the number of flu cases in February, in both the community and across our hospital sites.
Fourteen patients on three haematology wards at the Leicester Royal Infirmary have developed symptoms that have been confirmed as flu.
All necessary precautions were taken and these patients have been isolated to avoid an outbreak.
Visitors with flu-like symptoms have been asked to stay away from hospitals to avoid passing their infections to patients.
Three wards have been closed at a hospital after a major swine flu outbreak affected 14 cancer patients.
Leicester Royal Infirmary is trying to contain the spread of the virus, which was responsible for the flu pandemic in 2009/10.
The H1N1 swine flu strain is one of the dominant flu strains this winter and the current winter flu jab offers protection against it.
Glenfield Hospital in the city is also treating three seriously ill patients with swine flu, who are receiving extracorporeal membrane oxygenation (ECMO) treatment.
They were brought to Leicester from other parts of the country.
All 14 patients remain in isolation either in side rooms or on bays, a statement from the University Hospitals of Leicester NHS Trust said.
All patients are currently being treated with antiviral medication.
Staff are following protocols for preventing the spread of infection, including wearing masks, gowns and gloves and washing hands regularly.
On Monday, it was thought three people on the wards might have flu, and because these patients have very little immunity, it was decided to swab all patients and 14 were confirmed as positive.
The main wing at HMP Leicester was 'often chaotic' and there was a 'very high' rate of assaults on staff, an inspection revealed.Read the full story ›