Engineering group Charter International has confirmed speculation that it has received a second offer following a previous one from rival Melrose.The Daily Telegraph this morning quoted City sources as saying that Charter received a 870p a share offer last week, adding that there is speculation that the approach is from a party linked to US firm Lincoln Electric."The company notes today's press speculation regarding a possible offer for Charter," Charter said."The company confirms that it is in discussions with a potential offeror other than Melrose PLC regarding a possible offer for the company."It said the discussions are at an early stage. The offer throws up the prospect of a bidding war following two previous offers from Melrose.Melrose made a 780p-a-share approach on 29 June and an 840p-a-share bid on 15 July, both of which were rejected by Charter's board on the grounds that they undervalue the firm and its prospects.At 12.05pm, shares in Charter International were up by 23% at 762.5p.