Songo'o, 26, has played for Spanish clubs Albacete, Real Sociedad and Zaragoza and English outfits Sheffield Wednesday, Crystal Palace and Portsmouth.

He also has three caps with the Cameroon national team since 2008 and was a member of the Cameroon Under-23 and the French Under-19 squads.

Acosta, 30, has played for Greek clubs including Olympiakos Volos, Levadiakos and Aris and Romanian outfit Universitatea Cluj.