Former Newcastle striker Obafemi Martins is reported to be the latest transfer target for Birmingham boss Alex McLeish.
The Nigeria international, 26, left the Magpies for Wolfsburg in 2009 before joining Russian side Rubin Kazan last summer.
McLeish is keen to sign a striker this month but is unwilling to confirm his interest after being frustrated in attempts to sign Tottenham's Robbie Keane and Kenny Miller from Rangers.
"The board are trying very hard to bring someone in and are working around the clock in terms of negotiating with people," he said.
"After a couple of disappointments, I prefer not to discuss anyone publicly until the i's have been dotted and the t's crossed in any deal."
McLeish has been forced to defend his ability in the transfer market, though, after Birmingham's acting chairman Peter Pannu questioned the quality of some of his signings last weekend.
McLeish insists his relationship with Pannu and owner Carson Yeung is fine, and he is working closely with them to bring in new blood before the transfer window closes.
And he is happy with how the likes of Ben Foster, Craig Gardner, Nikola Zigic and Chilean winger Jean Beausejour are progressing.
Beausejour has made only four Premier League starts since arriving at St Andrews last summer but came off the bench to play a key role in Wednesday's Carling Cup semi-final win over West Ham.
"Beausejour was excellent," said McLeish. "Again, it takes time for people to settle.
"As you know, I went for British-based targets in the summer. I went for Charles N'Zogbia. If we had got him I wouldn't have gone for Jean.
"But Jean is settling in. He was out for six weeks with a knee injury which is something I couldn't legislate for.
"Also, when you bring in any signing, they don't necessarily go straight into your team anyway unless it's a big marquee signing.
"But you have to build a squad and some of the signings were coming to feel their way in and learn under the Barry Fergusons and people like that.
"Gardner came in. I said he wouldn't play in the first team to start with. He has got himself into the team.
"Like I said, Jean gave us a smashing performance and big Ziggy did well."
And the Blues boss added: "Just about every one of my signings are in the team. I can only play 11 players.
"Some signings are not signings which cost the earth but are signings you need to augment your squad."