People take part Party (PSOE) headquarters in a protest near to Spain's Socialists, following acting PM Pedro Sanchez negotiations for granting an amnesty to people involved with Catalonia's failed 2017 independence bid in Madrid, Spain, Nov 6, 2023. (PHOTO / REUTERS)

MADRID - Spanish police on Monday night used batons to charge against a group of people protesting, some using fire flares, outside the ruling Socialist Party headquarters in Madrid against a proposed amnesty law related to Catalonia's independence drive.

The clashes led to chaotic scenes of people running amid smoke and trash containers thrown in the streets, Reuters video footage showed.

Around 4,000 people attended the protest - including Spain's far-right party Vox leader, Santiago Abascal - and at least one person was detained, according to local media reports. Some protesters used tear gas, public broadcaster TVE reported.

Police used rubber bullets and smoke canisters to disperse the crowd as some pushed portable fences protecting the Socialist HQ and threw bottles at the police, according to El Pais newspaper

Police used rubber bullets and smoke canisters to disperse the crowd as some pushed portable fences protecting the Socialist HQ and threw bottles at the police, according to El Pais newspaper.

Spanish police and the central government's delegation in Madrid did not respond to requests for comment.

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The amnesty law has been proposed by acting Socialist Prime Minister Pedro Sanchez, who is trying to form a government after a July election produced no outright winner, in exchange for the backing of two Catalan separatist parties to a new term by Sanchez. The most high-profile beneficiary would be Carles Puigdemont who led Catalonia's failed 2017 independence bid.

The Socialists are reportedly nearing their negotiations with Puigdemont's party, Junts, while the proposed law has been fiercely criticized by conservative parties and judges who accuse Sanchez of jeopardizing the rule of law.

Wrapped in Spanish flags, some protesters chanted "Sanchez to prison" and "Puigdemont to prison" and others held a banner that read "Spaniards have the right and the duty to protect Spain".

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The protest was organized by a Spanish nationalist grassroots organization and smaller protests took place in other Spanish cities such as Barcelona.

"To attack the PSOE offices is to attack democracy and all those who believe in it," Sanchez posted on X, using the Socialist Party acronym in Spanish.