Chelsea keen to sign Fiorentina's Juan Cuadrado and Shaktar Donetsk's Douglas Costa in January

Chelsea are reportedly interested in signing Fiorentina winger Juan Cuadrado and Shaktar Donetsk midfielder Douglas Costa during the ongoing January transfer window.

According to the Daily Mail, the Blues have stepped up their pursuit of the duo and are willing to match the price expected by both the selling clubs.

Juan Cuadrado is Jose Mourinho's primary target, but the Serie A club are unwilling to let the player go, unless Chelsea match his £26.8m release clause.

The Italian club's manager Vincenzo Montella has made it clear that the player is not for sale, but is willing to let him go if the west London club meet their valuation.

"The issue around Cuadrado is very simple: he has a buy-out clause, which was written into his contract along with the club. If a team comes along and pays it, and the player wants to leave, then he can go," Montella said, as quoted by the Daily Mail.

On the other hand, the Stamford Bridge outfit are also keen on a move for Costa, whom the Ukrainian club are reluctant to sell and therefore playing hardball when it comes to the fee.

The report claims that Chelsea have upped their offer for the midfielder to £18.7m after their initial bid of £16m was rejected by the club. The midfielder has revealed that a move to the Blues will be a dream come true and Mourinho has welcomed the player's keenness to play for his team.

It was earlier thought that, the Brazilian midfielder was only a backup in case the deal for the Colombian World Cup star fails, but it is believed now that Mourinho is keen on bringing both of them to the Bridge in order to make up for the loss of Mohamed Salah and Andre Schurrle.

The Egyptian, as reports suggest is close to completing a move to AS Roma on a loan deal with the option of making it permanent at the end of the season. The German World Cup winner on the other hand is reportedly close to completing a permanent move to Bundesliga club Wolfsburg.