Athletic Club president Jon Uriarte said the Spanish Football Federation (RFEF) have failed to protect Nico Williams amid a "bombardment" of questions about his future, with sources telling ESPN that Barcelona are among the clubs interested in the winger.
Williams, 21, has been repeatedly asked in various interviews with the media while at the European Championship with Spain if he will remain at Athletic or if he would like to link up with international teammate Lamine Yamal at Barça.
Meanwhile, Barça president Joan Laporta said this week that the Catalan club would have the money to sign Williams, who has a release clause worth around €58 million ($63m), despite their financial problems.
Sources have previously confirmed to ESPN that Barça will prioritise signing a midfielder and a left winger this summer, with Williams among the targets for the latter position.
"Nico, a player who is committed to Athletic, has been subjected to a bombardment of questions about his future in an excessive and uncontrolled manner while at the European Championships," Uriarte said in a statement on Thursday.
"The RFEF have not been able to protect him.
"Respect between all the actors who make up football is a fundamental basis -- or that's how we view it at Athletic -- which does not include subjecting players with contracts at one club to public pressure to join other clubs."
Williams signed a new deal with Athletic at the end of last year, penning an extension at San Mames until 2027 rather than running down his contract and leaving as a free agent this summer.
However, his stock has continued to rise since then. He helped Athletic win the Copa del Rey last season, eliminating Barça in the quarterfinal, and has starred in Spain's run to the final at Euro 2024, where they play England on Sunday in Berlin.
He was named player of the match in the win over Italy and scored and assisted in the round-of-16 victory against Georgia.
Despite that, Uriarte insists that Athletic are able to fend off any interest in their prized assets as they prepare to return to the Europa League this coming season.
"There are no limits to Athletic's aspirations," he added. "We are demonstrating that we have an attractive project, a winning project for our players and our coach.
"The proof of that is that we have renewed the contracts of two of our internationals, Unai Simón (2029) and Dani Vivian (2032), while Nico signed a new deal last year until 2027. Various other sought-after players have also committed their future to the club.
"Athletic are financially, socially and in sporting terms capable of keeping players of the caliber of those named in its structure, including Nico."
Williams has maintained that his focus is purely on the Euros, rejecting the chance to talk about his future beyond the tournament.
He has been at Athletic, where he plays alongside his brother, Ghana international Iñaki Williams, since he was 11 years old and has made 122 appearances for the first team since making his debut in 2021.