Sporting Lisbon have reached an agreement with Nuno Mendes to increase his release clause.

The 18-year-old left-back has been a target for Manchester United, Liverpool, Juventus, Arsenal and AC Milan.

He recently signed a new five-year deal with Sporting, which included a €45m release clause.

But according to Portuguese newspaper Record, Sporting have now raised that amount to €70m.

The fee is a significant amount of money for a teenager with just 13 first-team appearances to his name.

United reportedly attempted to include Mendes in their deal for playmaker Bruno Fernandes.