Chelsea sponsors Three are reviewing their partnership with the club following the United Kingdom's decision to impose sanctions on owner Roman Abramovich.
The Russian oligarch has been hit with an asset freeze and a travel ban following his homeland's invasion of Ukraine as the UK imposes sanctions.
Abramovich has put the club up for sale, though any such deal will now depend on the UK government allowing it and ensuring Abramovich makes no personal gain from the transaction.
Chelsea signed a sponsorship deal with mobile phone network Three in 2020, though its continuation has now been thrown into doubt.
A Three spokesperson told The Athletic: "We are reviewing the situation and are in discussions with Chelsea FC.”
A 'General Licence' has now been issued to Chelsea which will allow the club to continue fulfilling its fixtures, football business and pay players and staff.
The government have sanctioned Abramovich because of his links to Russian president Vladimir Putin. Abramovich has also denied these links. However, a government document published on Thursday said Abramovich has maintained a 'close relationship for decades' with Putin.
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Chelsea can no longer sell tickets as a result of the sanctions. Only fans who are season ticket holders or have otherwise previously purchased tickets will be able to attend.
They are also under an effective transfer embargo, meaning new permanent or loan signings are banned. That is likely to apply to new contracts too, meaning the futures of Cesar Azpilicueta, Antonio Rudiger and Andreas Christensen remain uncertain, though the latter is expected to join Chelsea.