Martin O'Neill is remaining tight-lipped over any more targets after Sunderland completed the signing of Steven Fletcher.
The Black Cats are understood to be in the market for Manchester City's Adam Johnson and John Guidetti.
Sunderland boss O'Neill refused to be drawn on questions over the pair shortly after the signing of Fletcher from Wolves for a £12million fee.
"At this minute I cannot furnish you with many more details" said O'Neill.
"I was hoping that we might be able to do so, so if you allow me to be pretty hesitant on that one, I'll refrain because I really can't tell you anything on a serious note.
"I'm still trying to improve the team, obviously. Like everything else we need some more help and we're trying to provide that and get that there before next Friday evening.
"As good as they are, I don't think our players can do it on their own and the more help we can get there the better."
O'Neill was more forthcoming on the subject of his new signing, for whom the Wearside club made a number of bids before the Scot put pen to paper on a four-year contract at the Stadium of Light.
"I think Steven will be terrific for us. He's underrated, but not by me," added O'Neill.
"I think he's capable of scoring goals and linking play which is very important to us, and I think at 25 years of age he's got room to improve and get better.
"I'm delighted to have him for the next few seasons."