Arsenal have had an offer for Newcastle United's Bruno Guimaraes turned down -Credit:George Wood, Getty ImagesArsenal's opening offer for Newcastle United captain Bruno Guimaraes has been swiftly turned down, with the two clubs now engaged in direct negotiations for the Brazilian international.Guimaraes is scheduled to arrive in La Manga on Monday, where Newcastle's pre-season training camp is located. The midfielder is set for discussions with incoming Magpies manager Matthias Jaissle.Speculation has mounted in recent days surrounding an 80 million ($107.7 million) agreement, though it appears the two clubs have yet to reach that point. There were even suggestions that Guimaraes had been lined up for a medical with the Gunners, as per The Mirror.Donald Trump sparks outrage with Harry Kane World Cup commentsDonald Trump addresses Gianni Infantino's World Cup sale plans, amidst Kushner links -Credit:Anadolu, Anadolu via Getty ImagesHowever, the 28-year-old departed Brazil on Sunday aboard a commercial flight, prepared to rejoin his Newcastle teammates. Guimaraes still has two years remaining on his contract, plus an option for an additional year, with the northeast club hesitant to part ways with their captain.Newcastle have already secured a 100 million ($133.72 million) fee for Sandro Tonali from Tottenham Hotspur this summer and offloaded Anthony Gordon to Barcelona for approximately 75 million ($81.7 million). Despite his apparent interest in the transfer, Guimaraes will not come cheap for Arsenal.The Gunners' initial valuation of Guimaraes is reported to have been in the region of 70 million ($94 million), while Newcastle are believed to be demanding in excess of 80 million.Further offers are anticipated from the north London club following their unsuccessful first bid, with Arsenal understood to be the only party in contention.To listen to the latest episode of 'All Out Soccer' - CLICK HEREMikel Arteta has addressed Arsenal's objectives during the transfer window, with the club connected with Real Madrid's Vinicius Junior in addition to Guimaraes. The Gunners are preparing for an active conclusion to the transfer window."A lot is happening. We all know about the context of this transfer window," he said."From ownership to the board, the sporting director and myself, we know that we want to take this club to a different level. That is going to require a better squad, better individuals."We have identified where we have opportunities to grow and to improve and to evolve our game and what is going to be needed to achieve that. Hopefully, very soon we can start to put things in a very concrete way."