As Newcastle United have made their final £10 million offer to FC Twente for striker Luuk de Jong, the club have begun looking at alternative options in case the Dutch side once again turn down The Magpies' offer. Twente were said to be holding out for a £12 million offer, which Newcastle are not quite willing to match and the club have made it known that their £10 million offer is final. Reports earlier in the week suggested that German striker Borussia Mochengladbach had met Twente's valuation for de Jong, but the player himself prefers a move to St. James' Park and is hoping the two clubs can come to an agreement. Sky Sports News reported this morning that Newcastle are monitoring Manchester City's 19-year-old Swedish striker John Guidetti in case they can't agree a fee with Twente for de Jong. Guidetti spent last season on loan at Feyenoord, scoring 20 goals and racking in 8 assists in 23 games. City would be willing to part with him but it will take a decent sized offer from Newcastle to secure his signature. Newcastle are also looking closely at 19-year-old Inter Milan youngster Luc Castaignos (pictured above), who ironically joined the Italian side from Feyenoord last summer. 19-year-old Castaignos joined Inter Milan last year on a 3 Million deal from Feyenoord where he came through the youth ranks. He only turned out six times for Inter this season finding it tough to breakthrough the competition for first team places, scoring one goal. In the Dutch league with Feyenoord he scored 15 times in 37 games. The 6ft 2 inches tall striker previously scored goals at the 17-year-old and 19-year-old international levels but has yet to play at the senior Dutch team.