Tottenham have criticised three of their players for breaching coronavirus rules by attending a party over Christmas.
A picture on social media shows Argentina forward Erik Lamela, Spain defender Sergio Reguilon and Argentina midfielder Giovani lo Celso at a party.
“We are extremely disappointed,” Tottenham said in a statement.
West Ham have also reminded Argentina forward Manuel Lanzini, who also attended, of his responsibilities.
Lamela and Lo Celso were not involved in Saturday’s Premier League game at home to Leeds (12:30 GMT), while Reguilon – who joined from Real Madrid in September 2020 – was on the substitutes’ bench.
The Spurs statement added: “We strongly condemned the image showing some of our players with family and friends together at Christmas, particularly as we know the sacrifices everybody around the country made to stay safe over the festive period.
“The rules are clear, there are no exceptions, and we regularly remind all our players and staff about the latest protocols and their responsibilities to adhere and set an example.
“The matter will be dealt with internally.”
Lamela has made two Premier League starts this season while Lo Celso has made four.
Lanzini has featured in nine of West Ham’s 17 top-flight games in 2020-21 and came on as a substitute in Friday’s 1-0 win at Everton.
A West Ham spokesperson said: “The club has set the highest possible standards with its protocols and measures relating to Covid-19 so we are disappointed to learn of Manuel Lanzini’s actions.
“The matter has been dealt with internally and Manuel has been strongly reminded of his responsibilities.”
Tottenham’s Premier League home game with Fulham, scheduled to take place on 30 December, was called off three hours before kick-off because of the number of Fulham players testing positive for coronavirus or showing symptoms.
Meanwhile, Fulham have told BBC Sport they were looking into claims Aleksandar Mitrovic broke coronavirus rules by attending a New Year’s party – along with Crystal Palace midfielder Luka Milivojevic.
Images on social media, reported in the Sun, allegedly show the Serbia team-mates celebrating in London with at least seven other adults.
The mixing of households indoors is banned in London under the UK government’s tier four restrictions.
‘Mourinho must be so angry’ – Shearer analysis
Former England captain Alan Shearer, speaking to BBC Radio 5 Live:
[Tottenham manager] Jose Mourinho has been so critical and vocal of how the Premier League handled their situation [game called off against Fulham] which I totally disagree with him.
You have to accept we’re in strange and difficult times – if it has to be called off at whatever time then it has to be called off.
To then see some of his players breaking the rules and laws, particularly when millions of people are sacrificing so much not only in this country but around the world, Mourinho must be so angry.