Sunderland have not given up on their pursuit of Leicester City striker Leonardo Ulloa as they have reportedly increased their bid.

The Premier League champions are believed to be digging their heels in, with reports claiming that they will not sell to a rival.

Ulloa's relationship with Leicester is turning sour after he tweeted that he would not play again for the club after feeling "betrayed" by manager Claudio Ranieri.

Sunderland reportedly had a £3m bid rejected by the Foxes over the weekend, and Sky Sports News has claimed that their offer has increased to £7.5m.

Ulloa has been part of the club since his 2014 switch from Brighton & Hove Albion, and he scored six goals in Leicester's shock title-winning 2015-16 season.

In the current campaign, the striker has made 18 appearances in all competitions, starting just one league game and coming off the bench 11 times in the top flight.