Arsenal have signed Brazil defender Andre Santos from Fenerbahce on a "long-term contract" and for an undisclosed fee, the English Premier League club announced.
Santos's deadline day transfer came with Arsenal manager Arsene Wenger looking to bolster his defence following the Gunners' 8-2 thrashing by English champions Manchester United last weekend.
Arsenal are also in talks with Germany centre-back Per Mertesacker, who plays for Werder Bremen.