Palermo last night emerged as a potential threat to Celtic completing the £5m signing of Italian pair Gennaro Delvecchio and Massimo Donati.

The Parkhead club are pushing ahead confidently with moves for Delvecchio, a central midfielder with Sampdoria, and Donati, the AC Milan winger, after their interest was revealed in the Italian media earlier this week. Celtic have already spent in excess of £5m to recruit Scott Brown, Scott McDonald and Chris Killen this summer and senior figures at the club feel they have a strong chance of completing a twin raid on Serie A that would effectively double their expenditure.

It is hoped that the deals could be completed next week, yet the situation may be complicated by Palermo's interest in Delvecchio. Sampdoria officials last night described the 29-year-old midfielder as being "close" to joining the Sicilian club, who could be willing to agree a player exchange to facilitate the deal. Andrea Caracciolo and Marco Pisano are two at Palermo in whom Sampdoria have an interest as they seek to strengthen their squad for next season.

"We have been made aware of Celtic's interest, but Delvecchio may be close to joining Palermo," a Sampdoria spokesman said. "There are players at Palermo that we would like to have at our club and it's possible that a swap could be worked out. If there was to be a purely financial transfer then I think a fee of approximately 4m (£2.7m) would be sought for Delvecchio. We will see what happens over the next few days."

Celtic are hopeful the lure of Champions League football will ultimately help them win the race. Peter Lawwell, the Parkhead chief executive, this week stated that he would continue to support Gordon Strachan's spending plans and has backed that pledge by attempting to accommodate these ambitious moves.

Delvecchio, sent off last season for headbutting Marco Materazzi, would provide a physical presence at the core of Celtic's reconstructed midfield. A late developer in Italian football, he initially came to prominence with Lecce before moving to Sampdoria. The player won his first full cap for Italy against Croatia last season and has featured in most of Roberto Donadoni's squads for their recent Euro 2008 qualifying matches.

Donati has been loaned out to five different Serie A sides since his £10m move from Atalanta to Milan in 2001 and is now poised to make a permanent departure from the Champions League holders. Signing the 26-year-old would provide a different dimension on Celtic's left flank as they prepare for the defence of their league title and another European campaign.

The Parkhead club are also showing an interest in Maceo Rigters and have watched the striker in action for the Netherlands during the current European Under-21 championship. The NAC Breda player has a clause in his contract that means he is available for a cut-price fee, understood to be around £350,000. He is also wanted by Newcastle United.

McDonald and Killen have already been added to augment Strachan's forward options, so Celtic's tracking of Rigters poses further questions about the strikers currently in their squad. Both West Bromwich Albion and Cardiff City are considering moves for Craig Beattie but Maciej Zurawski has insisted he is not expecting to leave Parkhead this summer.

"I know nothing about this," said Zurawski, over questions that he could be sold. "Nobody at the club gave me a reason to feel myself unnecessary.

"I do not intend to go anywhere and I am not afraid of the competition from the newly signed strikers.

"The fact that the club is strengthening does not mean that someone wants to get rid of Zurawski. There will be a strong competition and this is nothing strange.

"My second season at Celtic was plagued by injuries and I scored only 10 goals. I agree that this was not a good season but is was not a catastrophic one. I was still among the club's top goalscorers."

Celtic, meanwhile, could also complete the acquisition of Jean-Joel Perrier Doumbe on a three-year contract next week.

The Frenchman, who scored the winner in the Tennent's Scottish Cup final, arrived at Parkhead on a short-term deal from Rennes in January and is currently a free agent.

"I am hoping to get something sorted out with Jean-Joel Perrier Doumbe and Celtic over the next couple of days," said Willie McKay, Doumbe's agent. "The player has been offered a three-year deal but has not signed anything yet because he has been away on holiday. We will be addressing the situation as soon as he returns."