Porto have announced that they are considering bids from Atletico Madrid for two of their star players.
The Spaniards have made an offer for Colombia striker Radamel Falcao and Portugal midfielder Ruben Micael.
25-year-old Falcao scored 38 goals for Porto last season, including 17 in their Europa League triumph.
24-year-old Micael joined the Portuguese champions in January 2010 but has since earned a call-up to the Portgual squad and scored twice on his debut in March.
Atletico are looking to replace Sergio Aguero who completed the move to Manchester City this summer in a deal believed to be worth 45million euros.
In a statement, Porto said: "We announce that we have received an offer from Atletico Madrid to sign Radamel Falcao and Ruben Micael, and this is being considered by the club".
Meanwhile, Porto have completed the signings of defender Eliaquim Mangala and midfielder Steven Defour for a combined fee of £11.4m from Standard Liege.