Newcastle United boss Sam Allardyce hopes to make four more signings.

His pursuit of the top-class defenders he wants to strengthen his squad appears to have gone cold and he is ready to leave pre-season training in the hands of his staff as he attempts to get his men.

Allardyce said: "Unfortunately, everything this week progressed to a certain level and has fallen on stony ground and I haven't been able to pursue something to the full conclusion of actually bringing him in for a medical to try to finish off a transfer.

"It has been an incredibly frustrating two weeks. It takes up a vast amount of my time because it is the most important thing for me to strengthen the squad we have at the moment, and particularly the defensive area.

"I'm building a very good backroom staff now and it's increasing by the week.

"I can delegate to them to carry on with the players the huge amount of training and conditioning they need to get ready for the start of the season, and be with them when I can.

"But really the main focus is to strengthen the squad as early as possible, and hopefully by August 11 we will have done that by three or four players."