Pompey have rejected two fresh bids for prized-asset Jamal Lowe.
It is understood the unnamed club have stepped up attempts to prise the winger, who scored 17 goals last season, away from Fratton Park.
Wigan and Millwall have been long-time suitors, with both clubs previously having £1.5m bids turned down for the former Hampton & Richmond Borough wide man.
The Blues value Lowe at £3m – and the latest approach is from one of those two clubs.
Pompey desperately want to retain Lowe, who can be a pivotal figure in their latest push for promotion from League One.
However, the 24-year-old has become unsettled at Fratton Park this summer in light of Championship interest.
The winger is keen to test himself at a higher level and has made his feelings known to the Blues’ hierarchy.
But he is under contract until the summer of 2020, with the club having an additional 12-month option.
Lowe scored in last night’s 11-0 demolition of UCD during a 45-minute outing.
Kenny Jackett’s side are currently in Dublin and will return to England on Friday ahead of Saturday’s pre-season friendly with the Hawks.