MADRID (AP) — The Latest on Catalonia's independence bid (all times local):
Two small groups of protesters have clashed in central Barcelona as a unionist demonstration of thousands was getting under way, with people throwing chairs at each other before local police separated them.
It was unclear what sparked the violence on Thursday and who was involved.
Footage obtained by The Associated Press showed chairs flying in both directions, as Barcelona's urban guard and regional police removed a few dozen protesters on each side.
A nearby demonstration led by a group of civil society groups opposing a separatist bid in Catalonia wasn't disrupted.
A separate protest of around 200 supporters of far-right and Spanish nationalist groups ended on Barcelona's Montjuic hill with speeches and the burning of a "Senyera," the unofficial flag that has become a symbol for Catalan separatists.
A spokesman with Spain's Ministry of Defense says that a military pilot has died after a fighter jet that was returning from a national day parade crashed in southeastern Spain.
The spokesman said the fighter jet was among four that participated in the parade in Madrid. Speaking anonymously, as its customary among civil servants in Spain, the spokesman said the Eurofighter plane crashed in Llanos de Albacete, a county some 300 kilometers (200 miles) southeast of the Spanish capital.
The spokesman said the pilot didn't have time to jump out of the jet, adding that the causes of the crash are under investigation.
—by Aritz Parra
Thousands of people waving Spanish and Catalan flags are marching in downtown Barcelona to celebrate Spain's national day.
Participants, some of whom had painted their faces in red and yellow, shouted "Viva Espana," or long live Spain, and "I am Spanish."
A few yelled "Puigdemont to prison," referring to Catalan leader Carles Puigdemont, who challenged Madrid by holding an Oct. 1 referendum on independence that the Spanish government said was illegal. The slogan of the march is "Catalonia yes. Spain, too," supporting autonomy for Catalonia, but within Spain as a whole.
The protesters walked down an empty boulevard heading to a central square in Barcelona. They booed when passing groups of regional police, who are seen by the unionists as having done too little to stop the separatist efforts to stage a referendum on the region's independence on Oct. 1.
A global human rights organization says Spanish police used excessive force when they faced peaceful protesters earlier this month during a disputed independence referendum in Catalonia.
The Oct. 1 vote went ahead despite a ban by Spain's top court. Under the country's Constitution, only central authorities can call votes on sovereignty matters and all eligible voters in Spain, and not only inhabitants of a region, should cast a ballot.
Police used batons on non-threatening protesters and caused multiple injuries, says Human Rights Watch in a report released on Thursday.
The U.S.-based organization says its researchers interviewed victims and witnesses in three locations and reviewed images from clashes across the northeastern region.
"At such divisive times it is especially important that authorities respect human rights, including freedom of speech and assembly, and the rule of law," said Kartik Raj, the organization's Western Europe researcher, calling for an independent investigation into the violence.
Catalan president Carles Puigdemont has reacted to the Spanish ultimatum to backtrack on his independence plans or face a suspension of regional powers, tweeting "We demand dialogue and the response is to put article 155 on the table. Message understood."
The separatist leader was referring to the clause that triggers never-used constitutional powers that Spain's conservative government has threatened to invoke if the independence bid is not dropped before an Oct. 19 deadline.
Puigdemont had earlier proposed to regional lawmakers to freeze the implementation of secession to allow time for negotiating independence with Spain. Prime Minister Mariano Rajoy has rejected any dialogue as long as secession is on the table.
The only other acknowledgement of Madrid's warning came from Puigdemont's deputy, Catalan vice president Oriol Junqueras, who tweeted to Rajoy: "A sincere dialogue is what the international community wants and what Catalonia expects, not confrontation and new threats."
Army troops and police are to march in Madrid as Spain's celebrates its national day, amid one of the country's biggest crises as its powerful northeastern region of Catalonia threatens independence.
King Felipe VI is to preside over the colorful annual parade Thursday as Spain awaits a response to a government request to Catalonia's leader to clarify by Monday if he has already declared independence, in which case Spain warns it may begin taking direct control of the region.
Catalan regional President Carles Puigdemont announced Tuesday that he was using the claimed victory in a banned Oct. 1 referendum to proceed with a declaration of Catalan independence, but proposed freezing its implementation for a few weeks to allow for dialogue and mediation with the national government in Madrid.