Brighton have announced the signing of the German midfielder Mahmoud Dahoud, whose contract at Borussia Dortmund expires at the end of this month. The 27-year-old will join on a four-year deal. The Syria-born Dahoud, capped twice by Germany in 2020, becomes Brighton’s third summer signing, after João Pedro and James Milner. The head coach, Roberto De Zerbi, said: “I’m excited to have Mahmoud in my team. I wanted him when I was at Sassuolo and I’m sure he is going to be a top player for us.” Dahoud began with Borussia Mönchengladbach before moving to Dortmund in 2017. He made 141 appearances for this season’s Bundesliga runners-up, although his game time was restricted after he had shoulder surgery last summer. West Ham have confirmed Manuel Lanzini will leave when his contract expires this month. The Argentinian midfielder joined in 2015 and has been linked with a return to River Plate in his homeland. West Ham’s manager, David Moyes, said: “We are sorry to see him go, but he deserves the opportunity to play more regularly elsewhere.” Arsenal have released Ainsley Maitland-Niles, who spent last season on loan at Southampton, but have said contract negotiations continue with Reiss Nelson, whose deal also expires this month.