Arsenal have agreed a transfer fee of about £17m (20m euros) to sell Belgium forward Leandro Trossard to Besiktas.

The 31-year-old has been given permission to travel to Istanbul to undergo a medical, for a fee of £15.3m (18m euros) plus £1.7m (2m euros) in add-ons.

Trossard, who is contracted with the Gunners until 2027, joined the club from Brighton for £21m plus add-ons in January 2023.

"Negotiations have commenced with professional football player Leandro Trossard and his club Arsenal regarding his permanent transfer," the Turkish Super Lig side said in a statement.

He has scored 36 goals and registered 34 assists in 174 appearances at Arsenal, helping Mikel Arteta's side win last season's Premier League title.

Trossard was a key player for Arteta last season, starting in the Champions League final defeat to Paris St-Germain and playing 21 times in the league.

Belgium reached the quarter-finals of this summer's World Cup, with Trossard starting all six games and scoring twice.

Arsenal set to target Club Brugge forward Tzolis

By Sami Mokbel, Senior football correspondent

The Gunners are set to accelerate their pursuit of Club Brugge attacker Christos Tzolis following Trossard's departure.

BBC Sport reported the Gunners' interest in the Greece international in June, and the club are now poised to move for the forward.

Club Brugge are anticipating an offer from Arsenal for Tzolis.

Sporting director Andrea Berta is working on the deal after his assistant Maurizio Micheli watched the 24-year-old play for Greece against Sweden last month.

Tzolis could be available for about £30m (35m euros).

Any move for him would be separate to Arsenal's interest in signing more high-profile attackers this summer.

They retain a long-term interest in Atletico Madrid's Julian Alvarez, who is the club's priority target, but it remains to be seen if a deal for the Argentina international is possible this summer with Barcelona and Real Madrid also interested.

Morgan Rogers is Arsenal's preferred option in their search for a versatile forward, with the club's efforts to sign the Aston Villa attacker set to accelerate once his participation at the World Cup with England is over.

Paris St-Germain winger Bradley Barcola is viewed as the alternative in the event of failing to reach an agreement with Aston Villa, who reportedly value Rogers at £130m.

Meanwhile, Arsenal recruitment specialist Micheli watched Georgia Under-21 international Andria Bartishvili play for Iberia 1999 against Flora in their Champions League qualifier last Wednesday, with sources indicating the Gunners are stepping up their efforts to land the teenage attacker.