Beijing Guoan declined to confirm Cedric Bakambu's reported 40-million-euro signing on Wednesday -- despite releasing a photo of what looks like the Congolese striker training with the club.

A Guoan spokeswoman refused to confirm or deny whether a picture of a training session in Portugal featured Bakambu, who announced his departure from Villarreal last week and said he was leaving to play in the Chinese capital.

It is the second time this week that Guoan have remained non-committal about Bakambu, after they told AFP in an earlier statement that they believed he quit Spain's Villarreal for "personal reasons".

Guoan's failure to confirm Bakambu's signing has raised questions over the move by the 26-year-old, which would be the most expensive so far in the current Chinese transfer window.

The lack of clarity comes after China's football association sternly warned clubs not to try to get round its 100 percent tax on transfer fees for foreign players, which was imposed to halt a dizzying series of record signings.

After Guoan released the training-session photo on Weibo, China's equivalent of Twitter, fans quickly identified one of the players as Bakambu.

"Because Bakambu is free now, in order to keep in good condition, at his wit's end, he came to Portugal to occupy his mind," one fan wrote in a light-hearted post.

"Coincidentally he ran into a certain CSL team training... Because he was travelling without gear, he had to borrow a training kit."

Reports in Spain and France said the 40-million-euro buy-out clause had been triggered to release Bakambu to play in Beijing, technically as a free agent.

The CFA this month warned it was watching to make sure clubs do not try to avoid the new tax, where a sum equivalent to the transfer fee has to be donated to a fund to develop youth football.

The tersely worded CFA statement came after Guoan and Chinese champions Guangzhou Evergrande were reportedly locked in a bidding war for Borussia Dortmund forward Pierre-Emerick Aubameyang.

Chinese media said Evergrande won the race for his signature -- but Evergrande later denied any interest in Aubameyang and repeated a pledge to field an all-Chinese team by 2020.

Beijing Guoan finished ninth in the 16-team CSL last season and appear determined to buy a goal-scorer before the start of the new campaign.