Arsenal have given Barcelona until the end of next week to sign Cesc Fábregas.Arsène Wenger is not prepared to countenance any deal for his 24-year-old captain unless he has time to reinvest the fee in a replacement before the transfer window closes on 31 August.

However, Pep Guardiola, the Barcelona head coach, said the club was prepared to "fight to the end" of the window to bring their former player back to Catalonia. He stated that the Arsenal captain was not their main priority with Alexis Sánchez, Udinese's Chilean winger, the current focus.

Guardiola said: "This year Arsenal has agreed to negotiate and we are working on [it]. Barcelona has made an offer [of £26m], Arsenal another [between £35-40m], and we have time until 31 August and we'll try to reach an agreement. There is a sum of money in the strong box set aside for this signing but if it doesn't work out it will be kept in the box for something else. We will fight to the end to try to get Cesc because we believe he will improve the team and the squad."

Wenger, though, hopes to keep Fábregas for another season. He insists that unless Barcelona finally end one of the longest-running recent transfer sagas by the close of the month, he will not be sold, saying recently: "We know that this story for Barcelona goes on for years now and we have to close that and for ourselves to focus on the season, hopefully with Cesc Fábregas."

Barcelona's sporting director, Andoni Zubizarreta, claimed that the club will not try to force through the deal. He said: "The position towards Arsenal is one of maximum respect because the club own the player; also towards the player. From there, our position is to try and see eye to eye [on a deal], creating proposals that may be of interest, while always maintaining the maximum respect. We don't have a style of doing things by force."

He said the negotiations for Sánchez were almost done. "All three parties have worked hard and we understand that the negotiations are coming to an end. Some endings are long-winded, but we hope that it is a happy one."

While Fábregas did not go on last week's tour of Asia due to a hamstring problem, Wenger hopes to include him in the team for Saturday's friendly against Cologne in Germany.

Guardiola dismissed any suggestions that Fábregas should excuse himself from the game by stating that he hoped he will participate if he is fit. "I think that Cesc has to do what Arsenal ask," the 40-year-old said. "For me I wouldn't like one of my players to say: 'Now I'm not training because I want to go.'"

While Fábregas remains a target, Guardiola said that with the club in the process of selling Bojan Krkic to Roma, Sánchez, who will cost around £30m, is the principal concern. The manager said: "The priority is an attacker. We have more players in midfield than in attack. Jeffrén [Suárez] also wants to leave, so the attack is more important."

Peter Hill-Wood, the Arsenal chairman, has stated that the club want Samir Nasri, who has been targeted by Manchester City, to stay on for another year at least. He said: "City seem to have more money than anybody else and they keep splashing it around all over the place. But our position is very straightforward: we don't want the player to leave."