Star striker Didier Drogba's Chinese club Shanghai Shenhua expressed outrage over his move to Turkish side Galatasaray on Wednesday, saying it breached his current contract and he was still their player.
Galatasaray and Drogba himself announced earlier this week that the Ivory Coast star had signed for the Turkish league leaders, apparently ending a two-and-a-half year deal with the Chinese Super League side.
"Currently, Drogba is still a player of the Shanghai Shenhua Football Club, and the contract between both parties is still within the term of validity," Shenhua said in a statement on its website.
"The club is deeply shocked by the Galatasaray Football Club's violation of rules by contacting a player still under contract."
Shenhua planned to appeal to football's international governing body FIFA over the matter, the statement said.
"The Shanghai Shenhua Football Club is collating all the evidence and materials and preparing to submit them to FIFA so as to protect the club's interests and prevent greater losses," it said.
A spokesman for the club declined to comment.
In a posting on his website, Drogba, who arrived in China last July, gave no clue as to the circumstances surrounding his exit from Shenhua, where he was reportedly earning $300,000 a week.
But Chinese media reported that Drogba had previously asked FIFA to nullify his contract after the club defaulted on payments following a shareholder dispute dating back to September.
Drogba's teammate at both Shanghai and previously Chelsea, French striker Nicolas Anelka, has also just left Shenhua, joining Italian giants Juventus on loan.