Catalonia remained on edge Monday, a day after millions voted for independence from Spain in a referendum that the central government used force to disrupt, severely limiting turnout but also raising questions about the legitimacy of a democracy that orders the police to beat voters. As the European Union spurned an appeal from the president of the Catalan autonomous region, Carles Puigdemont, to facilitate talks with Spain about what comes next, tens of thousands of students marched through the streets of Barcelona with their mouths taped shut, to express their frustration about the Spanish government denying them a voice.

Vídeo de l'espectacular marxa silenciosa de desenes de milers d'estudiants #caputxinada2017 pic.twitter.com/Ztuakv2lwk — Unis x la República (@unisxrepublica) October 2, 2017

This generation of Catalan youth's consent to be governed by closet Falangists of the PP elite just evaporated pic.twitter.com/j8IwgtZJ3a — Paul Mason (@paulmasonnews) October 2, 2017

There was particular outrage at the violence inflicted on voters by members of Spanish police forces who were called in to block the referendum after a Spanish court ruled that it was unconstitutional. The images of police officers beating voters and firing rubber bullets at polling places on Sunday stunned and horrified Catalans, and rage at the police only grew on Monday as more video clips were broadcast and circulated on social media.

Lanzan una silla a un agente de la Guardia Civil cuando trataba de entrar a un centro electoral https://t.co/4jzXimSS8c pic.twitter.com/sw5lDFviqU — Europa Press (@europapress) October 1, 2017

Aquí un ciudadano de uniforme siguiendo órdenes y protegiendo el Estado de Derecho. #CatalanReferendum pic.twitter.com/x7h51gEzqt — Alberto Pradilla (@albertopradilla) October 1, 2017

@policia disparando antes de irse.Dejando bien claro su posición.Ahora que alguien me defienda esta actitud #CatalanReferendum pic.twitter.com/cmkIMvzM4i — Dani Cordoba (@Dani_CCardenas) October 1, 2017

In Barcelona, hundreds of protesters blocked traffic outside the headquarters of the Spanish national police force in the city, where Catalan nationalists were tortured during the dictatorship of Gen. Francisco Franco. As protesters screamed abuse at the Spanish police inside the building, the autonomous Catalan police force, the Mossos, was called in to keep the peace.

+150 estudiants es manifesten a les portes de la Policia Nacional a Via Laietana. Crits "d'independència i d'assassins" @btvnoticies pic.twitter.com/OfVi7yGxyu — eduard colldecarrera (@educollde) October 2, 2017

Protest outside Policía Nacional station in BCN: more Mossos arrive to make a barrier between crowd and PN pic.twitter.com/UsyhLDeWgm — Zach Campbell (@notzachcampbell) October 2, 2017

Ahora mismo en Vía Laietana frente a la Jefatura Superior de Policía pic.twitter.com/ztk52EA1h3 — Antonio Maestre (@AntonioMaestre) October 2, 2017

Els Nacionals han aprofitat un moment de distracció per treure les furgonetes i escapar de la manifestació pic.twitter.com/fUgpqsRPSl — Ferran Pallàs (@ferranbdn) October 2, 2017

Outside Barcelona, in the town of Calella, residents demanded that Spanish Guardia Civil officers be withdrawn after video showed that plainclothes officers had attacked protesters outside their hotel.

Esta madrugada en Calella ( Barcelona) un grupo de Guardia Civiles de paisano salieron del hotel a dar palizas pic.twitter.com/FfNEUGv9EN — Irreverent (@Nen__17) October 2, 2017

Aquí teneis un vídeo en el que se ve a los Guardias Civiles de paisano con las porras extensibles https://t.co/ccSxwNB816 — Antonio Maestre (@AntonioMaestre) October 2, 2017

The officers were evacuated from Calella after a day of angry protests.

La gent concentrada al C. Bruguera impedeix la sortida de la policia a la NII al crit "al carrer serà sempre nostre" #1Ocalella pic.twitter.com/5UdFk5wc9f — Ràdio Calella TV (@RadioCalellaTV) October 2, 2017

Un grupo de fascistas de Calella golpean los vehículos de la @policia cuando abandonan el pueblo, "escoltados" por los @mossos pic.twitter.com/C4rk1bqScm — Publio C. Escipión (@c_escipion) October 2, 2017

Rage at the national police was not dimmed by the revelation that officers billeted at the port of Barcelona posed with the Spanish flag for a triumphal victory photograph after attacking Catalan voters.

La Policía Nacional posa en el puerto de Barcelona tras las cargas del 1-O https://t.co/WNJudd9wfN pic.twitter.com/FjVQKrzwah — La Vanguardia (@LaVanguardia) October 2, 2017

How the crisis can be defused without further violence remains a mystery, but the next step for Catalans seeking to put pressure on the government of Spanish Prime Minister Mariano Rajoy is a general strike called for Tuesday.

Els cartells reclamant la Vaga General (o Aturada Nacional) ja són als carrers pic.twitter.com/Rd9D0cblt1 — Carles Garcia (@CarlesGN) October 2, 2017

The planned action appears to have widespread support, even from opponents of independence who feel that Spain denied them their democratic rights by hampering the referendum. Major Spanish trade unions refused to sanction the strike, but it was supported by the city of Barcelona and important Catalan cultural and sporting institutions, including FC Barcelona and the Sagrada Familia cathedral.

Demà, aturada general. Se suspenen tots els actes institucionals i els serveis no imprescindibles per al funcionament de la ciutat tancaran. — Ajuntament de BCN (@bcn_ajuntament) October 2, 2017

FC Barcelona joins the country wide strike called for by Table for Democracy and therefore the Club will be closed tomorrow. — FC Barcelona (@FCBarcelona) October 2, 2017

The Basilica of the Sagrada Família condemns the violence experienced yesterday in Catalonia and will be closed all day tomorrow, 3 October. — La Sagrada Família (@sagradafamilia) October 2, 2017

The images of police violence enflamed opinion in Catalonia and abroad, yet instilled fear locally and likely had a chilling effect on voter turnout, leaving the legitimacy of the result in doubt. A Catalan activist who asked to be identified only by his first name, Jordi, because he feared retribution from the Spanish authorities, told The Intercept that he was distraught to hear that turnout for the referendum had been limited to about 42 percent and blamed the images of police beating voters for convincing many supporters of independence to stay home on Sunday. The activist also said that he feared that the Spanish government might be planning to arrest the Catalan president to provoke a crisis on the streets that would justify calling in a far larger security force, perhaps including the military. The sense of frustration and hopelessness was expressed across Catalonia on Monday night in a form of noisy protest known as a casserolada, in which keys are shaken and casseroles, pots, and pans are banged on loudly.