Celtic have rejected Arsenal's latest bid for left-back Kieran Tierney, Sky Sports News understands.
Arsenal's offer was worth in the region of £25m but it is understood Celtic were unhappy with the structure of the bid and want more cash upfront rather than in add-ons.
The Scottish champions are reluctant to sell their top asset unless the deal meets their valuation.
Sky Sports News understands that Serie A side Napoli remain interested in a deal for the Scotland international.
Tierney, who is under contract until 2023, was restricted to 21 league appearances for Celtic due to a hernia problem. The 22-year-old is currently recovering from surgery.