O'Neill is aware competition is fierce as Villa look to improve on last season's sixth placing in the Barclays Premier League.

The former Celtic manager said: "It takes a bit of time. We've got targets in mind of course and want to do business as promptly as we possibly can.

"But the people we want to try to improve this club are players you can almost automatically assume are key players at other football clubs.

"These are people it might be difficult to prise out of their current clubs. We need to improve our squad and I know that. But it's a fact that improving the squad gets harder as you progress. We've just finished in sixth place in the Premier League and I think the supporters will agree that we have progressed over the last two years.

"But to improve on what we now have means bringing in even more quality - and the competition for quality players can be fierce."