Arsenal have been told by Celtic to fork out £25million for left-back Kieran Tierney after offering just an initial £15m, according to reports.
Unai Emery is eager to bring in the talented Scotsman this summer to give competition to Sead Kolasinac and Nacho Monreal, whose contract expires this summer.
And according to the Sun, Arsenal offered the Scottish champions £10m too little for the 22-year-old, who created five assists in 20 games during the 2018-19 league season.
The report also claims the north London outfit tried to tempt Celtic by offering fringe or youth players, such as Carl Jenkinson, Jordi Osei-Tutu and Emile Smith Rowe as part of any deal.
Celtic are open to letting Tierney leave in the summer transfer window but they will hold out firm until their valuation is met.
Tierney, who joined the Hoops' youth system all the way back in 2005, has a contract until 2023 so would demand a significant transfer fee from any suitors.
Emery is eager to bolster Arsenal with young and exciting players this summer as he looks to help re-build the squad after missing out on Champions League football for a third season running.
Arsenal have yet to make a signing this summer but have been linked with the likes of William Saliba, Yannick Carrasco and Ryan Fraser.