Leicester City have been told to up their initial €20 million offer for Sporting forward Islam Alimani, according to A Bola in Portugal.
The club have demanded that the Foxes increase their bid by €10 million if they want to sign the striker.
The Algeria international found the net 27 times in 33 league appearances during the 2015-16 campaign, which helped take Sporting to a second place finish.
Leicester may be forced to splash out on the forward now that their star striker Jamie Vardy looks set to join Arsenal.