A man takes photos of fires that burn toward the end of a Catalan pro-independence protest outside the Camp Nou stadium in…
A man takes photos of fires that burn toward the end of a Catalan pro-independence protest outside the Camp Nou stadium in Barcelona, Spain, Dec. 18, 2019.

BARCELONA - One of the world's most-watched soccer matches was played Wednesday night amid heavy security as authorities sought to keep Catalonia's separatist movement from disrupting the game between Barcelona and Real Madrid.

While the game in Barcelona's Camp Nou stadium began without incident, some riot police clashed with protesters in the streets outside, and plastic trash cans were set on fire.

The match, which drew nearly 100,000 spectators, was halted briefly when a few dozen balls were thrown onto the field, some of them bearing a message urging the Spanish government to open a dialogue with the separatists.

Thousands of police and private security guards were deployed in and around stadium as nearly 100,000 fans attended. During the street clashes, riot police used batons to force the crowd back.

Some protesters fought between themselves, while others threw objects at police lined up behind shields. At least four trash cans were set on fire, and a smell of smoke wafted into the Camp Nou.

Masks depicting Barcelona's Lionel Messi are confiscated by security personnel as Barcelona supporters enter at the Camp Nou stadium, ahead of a Spanish La Liga soccer match between Barcelona and Real Madrid in Barcelona, Spain, Dec. 18, 2019.

The game between Spanish league leader Barcelona and its fierce rival Real Madrid was broadcast to more than 650 million people worldwide, according to the home team. The separatists sought to take advantage of the global media coverage to promote their bid for independence from Spain.

The game, known as El Clasico, was postponed from Oct. 26 amid violent protests by the separatists.

As crowds entered Europe's largest soccer stadium Wednesday night, security guards confiscated masks of Barcelona's Argentine star Lionel Messi from supporters, apparently to ensure they could be identified on closed-circuit cameras if they broke the law.

As the game began, some fans held up blue signs saying “Spain, Sit and Talk” and “FREEDOM.” Others chanted, in Catalan, “Freedom for the Political Prisoners.” Those messages referred to the Spanish government's refusal to discuss the wealthy northeastern region's independence, as well as the recent imprisonment of nine of the movement's leaders convicted for their roles in a failed 2017 secession bid.

A shadowy online group called Tsunami Democratic, which was behind the protest, had posted a message on social media saying: “Hello, world! Tonight Tsunami has a message for you.”

Protest organizers said that over 25,000 people signed up to demonstrate near the Camp Nou stadium in Barcelona, Catalonia's capital, although it was hard to distinguish between protesters and fans.

There was a festive atmosphere before the game, though some protesters briefly blocked main roads to the stadium.

The Barcelona team asked its fans to behave with civility and not to affect the match.

Police officers respond during a protest by Catalan pro-independence demonstrators outside the Camp Nou stadium ahead of a Spanish La Liga soccer match between Barcelona and Real Madrid in Barcelona, Spain, Dec. 18, 2019.

Francisco Sanchez, a 60-year-old mechanic, was outside Camp Nou hours before the match. He did not have a ticket, but was one of several protesters who distributed small blue banners with the message urging Spain to begin a dialogue.

“I hope this movement will make our leaders realize that they have to lay off the law and start taking,” he said. “This can't be solved with violence, but through words.”

Miguel Angel Gimenez, a 42-year-old policeman in a Barcelona shirt and scarf, drove with a friend over 700 kilometers (430 miles) from the southern region of Murcia to attend the match.

“Our friends back home told us we were crazy to cross half of Spain to go to a game that might not be played,” he said, adding that “everything is quite calm. There is lots of security.”

The U.S. Consulate in Barcelona advised people to avoid the area or exercise caution if they are nearby.

Henrik Noerrelund, a 55-year-old electrician from Denmark, flew in with his wife to attend his first Barcelona match after a lifetime supporting the club.

“In my parts, they used to say politics and football don’t mix, but today you have to accept it,” Noerrelund said. “It's there, you cannot separate it, you have seen it for many years, and I don't think they can manage to separate it and just play football.”

Separatist sentiment grew sharply in Catalonia during the global recession that hit Spain hard. The 7.5 million residents of Catalonia are about equally divided by the secession question, according to polls and election results.

Separatists have used the Camp Nou stadium as a protest platform for years. They shout “Independence!” at a set time during matches and sometimes unfurl banners.

Police officers bar the way to Catalan pro-independence demonstrators during a protest outside the Camp Nou stadium ahead of a Spanish La Liga soccer match between Barcelona and Real Madrid in Barcelona, Dec. 18, 2019.

The Barcelona team has walked a fine line between supporting its fans' right to free expression and aligning itself with the greater interests of Catalonia. Many feel it does not fully support secession so as not to anger its Catalan fans who are not separatists or its millions of supporters across Spain.

With its slogan ”More than a club,” it presents itself as a Catalan institution, aligned with the region's proud cultural traditions and language, which is spoken along with Spanish in the semi-autonomous region.

Its rivalry with Real Madrid has a decades-old political undercurrent, with many Catalans — just like residents of other regions in Spain — seeing the capital's team as a symbol of domineering, central power and a hallmark of Spanish unity and authority.

Madrid supporters, in turn, see Barcelona as representing a traitorous region that wants to break up Spain. For many years, some Barcelona fans held up a massive banner at games that read “Catalonia is not Spain.”

Players from both teams usually get along very well. The Spanish national team that won the 2010 World Cup and two European Championships was packed with players from both sides.

Security is always high whenever they play — just like at many soccer matches between fierce rivals — but there is no history of violence at the games.

Tsunami Democratic carried out its first major action in October when it organized a large protest after several of the secession movement's leaders were sentenced to jail for their role in a failed secession bid in 2017.

A call by Tsunami Democratic led to thousands of angry protesters gathering at Barcelona's airport.  A massive street fight broke out between the most radical protesters and police inside and outside the terminal, and about 150 flights were canceled as ground transport was halted for hours. Protests by separatists left more than 500 people injured, half of them police.