West Ham may be blocked from paying the next installment of their fee for Nikola Vlasic to CSKA Moscow.

CSKA sold the Croatian to West Ham for £25.7m last summer and the next installment is scheduled for August.

However, given the British government's sanctions on Russia, the Hammers may be prevented from fulfilling their commitments to CSKA.

The Irons wish to pay, but local government could block them, reports the Guardian.

The matter could be taken to FIFA, though CSKA may find themselves snubbed after the governing body's suspension of Russia from the World Cup.