Arsenal defender Laurent Koscielny has welcomed new signings Lucas Perez and Shkodran Mustafi.

The Gunners are expected to announce the both signings on Tuesday for a combined fee of £52million as Arsene Wenger concludes his summer business following a protracted search for improvements at both ends of the field.

"First of all, we have a few people injured. When you start the season with Welbeck injured, Mertesacker and then Gabriel out, it is difficult," Koscielny told Arsenal's official website.

"You need to have some players, because when you play every three days in September, October and November you need a big squad to fight in every competition."