Arsenal manager Arsene Wenger admits he is keen to sign another defender following the departures of veteran centre-halves Sol Campbell and William Gallas.

With Gallas unable to agree a new contract when his deal expired at the end of last season and Campbell joining Newcastle this week, Wenger has been left with just Thomas Vermaelen, new signing Laurent Koscielny and Johan Djourou to fill his two centre-half positions.

Wenger, who has also released former Manchester United star Mikael Silvestre, believes he ideally needs four or five central defenders and he is keen to add to his options before the transfer window shuts on 31 August.

"We are still on the search because at the moment we only have three centre-backs and we have seen last season you needed five," he told Arsenal's website. "I believe we need at least four because we have some other players who can fill in this position but overall we are still on the search.

"There are plenty of names that we consider and we analyse. We look at the financial possibilities and the technical potential. But it is impossible for me to come out with a name."