Arsenal are firming up the their interest in Celtic fullback Kieran Tierney.

The Sun says Arsenal are interested in the 19-year-old Scotland international.

The Gunners have reportedly been watching Tierney for the past 18 months as Arsene Wegner searches for a long-term replacement for Nacho Monreal, 30.

Pep Guardiola's Manchester City are also interested in Tierney, who they have scouted a number of times in the Champions League this season.