People in at least 50 cities across Spain have held demonstrations in support of the country’s unity, which is apparently at risk amid a plan by the northeastern region of Catalonia to declare independence.

Tens of thousands gathered in the capital Madrid and also Barcelona, the regional capital of Catalonia, on Saturday to call for dialogue that could defuse Spain’s worst political crisis in decades.

The pro-unity rallies come amid souring tensions over Catalonia’s recent referendum of independence.

Catalan leader Carles Puigdemont and officials in the regional parliament have vowed to push ahead with a plan to declare independence from Spain despite Madrid’s opposition to the vote, which manifested itself in unprecedented police violence on the day of the controversial vote last week.

Many of the protesters in Madrid were dressed in white and waved Spanish flags, chanting, “Viva España” and “Viva Cataonia”.

“I’ve come because I feel very Spanish and makes me very sad what’s happened,” said a demonstrator while wearing a “Catalonia, we love you” sticker. “I wanted to be here for unity, because I also feel very Catalan. My family lives in Catalonia,” said the 47-year-old.

Protesters in Barcelona, many of them also dressed in white similar to pro-unity marchers in dozens of cities, called on regional leaders and the central government in Madrid to engage in talks, saying the prospect of Catalonia out of Spain would be disastrous for both sides.

“I‘m very worried. This will end badly and everyone will lose,” said a 61-year-old protester in Barcelona, adding, “This is producing a social rupture in Catalonia and this has to be resolved through dialogue, never via unilateralism.”

Madrid continues to brand the Sunday referendum, in which a yes vote to independence allegedly won, as illegal and authorities have suspended a Catalonia parliament session planned for Monday, when lawmakers are set to endorse the results of the referendum and declare independence.

The government of Prime Minister Mariano Rajoy has rejected a request by Puigdemont for holding talks, saying he and other Catalan officials should first give up independence campaign altogether and then talks could begin on more privileges for the economically-vibrant region.