BARCELONA, Spain — After nearly two weeks of largely peaceful protests across Spain, police officers in riot gear used force to clear hundreds of protesters from a central square in the Catalan capital on Friday morning.

Officers arrived around 7 a.m. to Plaça Catalunya, where activists have been camping out for days as part of an ongoing nationwide protest over high unemployment and other political and social ills in Spain.

The police, part of a Catalan squad, used batons and compressed-air guns that fired blanks to eject people who were sitting on the ground when they wouldn’t leave voluntarily, the authorities said. A journalist with Agence France-Presse who was present at the time reported seeing rubber bullets fired as well.

Witnesses posted video and photographs online of the police hitting seated protesters.

A Barcelona blogger who writes on Twitter as Nadie also pointed to video posted on YouTube that showed that the clearing of the square was carried live on Spanish television.

This video shows a shot of some kind being fired at protesters by a police officer:

El País newspaper reported that 121 people were lightly injured, including 37 police officers, “as the result of a police charge” on the protest camp. Video posted on the Web site of 20minutos, a Spanish news site, showed the officers charging at protesters.

Citing a spokesperson for the authorities, who would not be named according to Catalan policy, Bloomberg News reported that about 300 people had been removed from the square.

Onlookers said that after the square was cleared government cleaning trucks swept through, and the possessions of the protesters, including P.A. equipment for giving speeches, were dumped inside the trucks. The authorities said that butane-gas cylinders were also removed, as a precaution; Plaça Catalunya is traditionally the site of celebrations for the city’s soccer fans, and the Champions League final, between F.C. Barcelona and Manchester United, is scheduled for Saturday.

By noon on Friday, the sweep was over, though the mood was tense; officers in riot gear remained; a police helicopter hovered overhead; and the area, near a major shopping district, was cordoned off. Activists — some wearing signs identifying them as such, or holding placards that read “resistancia pacifica,” or, peaceful resistance — sat on the sidewalk beyond the square. They held multicolored flowers and sang and chanted “No estamos solos” — we are not alone. A few tried to lighten the mood: as the afternoon grew hot, one man offered squirts of sunscreen to fellow activists, curious tourists and even the police (they declined).

The authorities said that police had left the area by 1 p.m. El País reported that protesters had returned to the square. Just a few hours after the arrival of police officers, protesters were passing out fliers decrying their behavior, and calling for people to return to the square at 7 p.m. to protest. On Twitter, an appeal went out for protesters to “bring flowers” when they returned. In the square and elsewhere in the city, there has been a nightly banging on pots and pans at 9 p.m. to show support for the movement.



Traer flores a la concentración de las 19h en Plz.Catalunya #27mcolon #bcnsinmiedo #acampadabcn #confloresalas7 Acampadabcn

Acampadabcn

Carlos Delclos, 28, is an adjunct professor of sociology at a university, Universitat Pompeu Fabra, in Barcelona. Alerted by a text message, he came to the square early this morning, to help stage a counterdemonstration as the police moved through with trucks to collect people’s belongings.

Mr. Delclos, a Spaniard who grew up in Houston and who holds dual United States-Spanish citizenship, said he was attacked by police as he sat blocking the trucks. “The riot cops would try to make way for the trucks by just hitting protesters with batons,” he said in a phone interview on Friday. “They started hitting the people on the ground. As that happened, I got up and I turned to run, and one pushed me down and I fell forward on my stomach, and then they were hitting on my back.” Mr. Delclos said he was also hit on his legs and wrist. He left the square and walked to a nearby hospital, where he was treated for bruises and a sprained wrist.

Mr. Delclos was released from the hospital in the early evening and said he planned to return to the square, where he had been regularly since the protests started nearly two weeks ago, fueled by anger at economic disparity and other problems in Spain. “I am one of those people that has light injuries,” he said. “It’s not too much to ask of me.”

Update: Here is a photograph of Plaça Catalunya taken by a reader, Víctor Riverola, at 7 p.m. local time on Friday evening showing that thousands of protesters returned:

Melena Ryzik reported from Barcelona and Robert Mackey contributed additional reporting from New York. Thanks to the readers who submitted links to video of the police action.