Sunderland have stepped up their efforts to land some of Steve Bruce's transfer targets by tabling formal bids for Lee Cattermole and Fraizer Campbell.

Press Association Sport understands the Black Cats have made an undisclosed offer to Wigan for midfielder Cattermole and also agreed a fee with Manchester United for striker Campbell which could eventually amount to in excess of £5million.

In addition, it is also understood they have made an approach to Portsmouth for England striker Peter Crouch, thought to amount to £11million, while their interest in Tottenham's Darren Bent is ongoing.

However, while the Campbell situation looks promising - it is understand the 21-year-old could head to Wearside for a medical and to discuss personal terms over the weekend - Sunderland could face more of a battle to reach the same stage with some of the other men in their sights.

Bruce, then in charge at Wigan, paid Middlesbrough £3.5million for 21-year-old Cattermole last summer, and has been linked with a move for him ever since he himself headed for the Stadium of Light in June.

Asked at the time if he would attempt to sign any of his former players, he said: "I know the Wigan squad and let me tell you, they might be only a little, small squad and a little, small team and a little, small town, but by God, they have got some big players.

"It would be wrong of me to talk about them, but I have also got a huge respect for the people who run Wigan, from the chairman to the chief exec.

"Of course, there would be a couple of people I would court, but I am not going to tell you."

Sunderland's bid is undisclosed, although some reports have suggested Cattermole could cost them as much as £7million.