Las Palmas plan to wear shirts embroidered with the Spanish flag during their game against Barcelona, with Sunday's match at Camp Nou reportedly under threat due to outbreaks of violence surrounding the Catalan independence referendum.
Barcelona's board met on Sunday morning to discuss whether the match should go ahead after footage emerged of violent clashes involving riot police, with voters being forcibly removed from some polling stations.
Videos shared on social media also showed police using batons and rubber bullets in confrontations with protesters. A statement from the Guardia Civil said officers were "resisting harassment and provocation" while completing its functions "in defence of the law".
Spain's national government have ruled the referendum to be unconstitutional and illegal, although it has retained prominent support from the likes of Barcelona defender Gerard Pique and former Barca head coach Pep Guardiola.
The club's vice president Jordi Cardoner described the vote as "an important day in the history of our country" this week, before insisting the LaLiga leaders must "focus on football".
In a statement issued on Sunday, Las Palmas made their stance in support of a unified Spain clear and accused Barcelona of being complicit in making the game "more than a sporting event in compliance with the [fixture] calendar".
"UD Las Palmas could have been limited to being a silent witness of this historical crossroads or to take sides. We settle for the second [option]," the statement read.
"We have decided to embroider our shirt with a small Spanish flag and today's day, October 1, 2017, to testify without strings our hope in the future of this country and in the goodwill of those who live in it, in search of the best understanding.
"No matter how far away the Gran Canaria Stadium is, we have never felt the least temptation to be part of a country other than this. And however complex the situation may be, we will always rely on simplifying it to better understand and find solutions."
The statement added: "Today, what we do is very simple. With the Spanish flag embroidered on our kit we want to vote unequivocally, in an imaginary consultation that nobody has summoned us to. We believe in the unity of Spain.
"We do it from the moral authority that you want to grant to the region farthest from the capital of this kingdom. We do it to tell the world that we feel pain for what is happening."
Pique tweeted a picture of him at a polling station on Sunday, while former Barcelona great Xavi condemned the scenes in his homeland.
"What's happening in Catalonia is shameful," he said in a video widely shared on social media.
"It's unacceptable that, in a democratic country, people can't vote."