Premier League clubs are circling Porto for Jackson Martinez.
The Colombia international has announced he intends to leave Porto at the end of the season.
The Sun says Arsenal, Tottenham and Liverpool are all keeping tabs on Martinez's situation, along with Manchester United, which have scouted Porto twice since the closure of the winter market on Monday.
"I am clear that next summer will surely mark my departure to a new club," said Martinez.
"In Porto, the players are valued and gain experience. This team has opened me up to the possibility of playing in a dynamic and tactical football competition, I appreciate that."
