(CNN) -- Thousands of mourners defied government forces and took to the streets Friday in Salmabad, Bahrain, to attend the funeral of Ahmed Ismaeel, who was killed last week in anti-government protests, witnesses told CNN.
"Despite this ruling family we will be protesting even if we all become martyrs," said a man's voice over a loudspeaker. "You are the free people, do not bow to them!"
To that, the crowd chanted, "Just to God we will bow!"
CNN cannot independently confirm the authenticity of the video.
The funeral procession was held without incident, but clashes broke out during the burial between mourners and riot police, a witness said.
Several people were injured when protesters hurled petrol bombs and rocks and police responded with bird shot and tear gas, the witness said.
Activist Ala'a Shehehabi of Bahrain Watch said she, too, attended the funeral. "It was seething with anger and full of anti-government chants," she said. "As we were leaving the burial we were attacked by the riot police. We saw the police coming in and got in our car."
Shehehabi shot video that she said showed teargas and shotgun pellets being used on the demonstrators.
"It was use of excessive force," she said. "The policy is collective punishment. They target everyone on the street that's doing anything. It's bad. It's wrong. It's happened to every funeral I've been to."
Bahrain Watch also accused police of taking part in looting stores believed to be sympathetic to protesters. The organization pointed to a video shot on April 10 in a store in the village of Nuwaidrat where police officers failed to stop a mob from ransacking the store. One officer can be seen in the video taking water off the shelf and another appears to instruct looters to break a security camera.
"This video is just the latest evidence of the culture of impunity prevailing among Bahrain's security forces, despite the government's claims that they are being trained and reformed," Bahrain Watch said in a statement.
Bahrain's Ministry of Interior said it is investigating the incident.
Abdul-Aziz bin Mubarak Al Khalifa of the Bahrain Information Affairs Authority , said there were injuries, but no deaths in the clashes.
"There was definitely tension in yesterday's demonstration and the security forces had to intervene in order to stop the violence committed by some rioters," he told CNN.
Shehehabi of Bahrain Watch says she believes the police crackdown was an attempt by the government to clear away protesters before next weekend's planned Formula 1 Gulf Air Bahrain Grand Prix.
In a news release issued Friday, the race's governing body said its president traveled last November to Bahrain and met with "a large number of decision-makers and opinion formers, including elected Shia members of parliament, the president of the Bahrain Independent Commission of Inquiry, ambassadors from the European Union countries, the Crown Prince, the Interior Minister and many members of the business community.
"All expressed their wish for the Grand Prix to go ahead in 2012," it said.
But Bahrain Watch's Shehehabi said there was growing resentment among Bahrainis to the planned event. "Formula 1 is giving the perception that is intrinsically linked to the regime. It's its pet project. Going against Formula 1 is going against the government."
That view was supported by the Bahrain Youth Coalition, which has organized a number of anti-government protests.
"The vast majority of Bahraini people have clearly expressed their objection to F1 to take place in Bahrain," the coalition said. "Insistence to hold the race in our occupied land presents a great provocation to the feelings of people and disregards the blood that is shed every day."
The Bahrain International Circuit said that the race will bring economic, publicity and public relations advantages to the country, and denied that it is a government pet project.
"Close to 100,000 fans from all sectors of the community attend the three-day race weekend each year, and even more watch it live on TV across the country. This clearly indicates how highly the Bahrain Grand Prix is valued by Bahrain's people and not just by the government," BIC said.
In a statement, Human Rights Watch said the decision to go ahead with the race "gives Bahrain's rulers the opportunity they are seeking to obscure the seriousness of the country's human rights situation."
"Formula 1 promoters say their decision to race in Bahrain should not be derailed by political considerations, but the ruling family will attempt to portray today's decision as a political statement of support for its repressive policies," said Tom Porteious, deputy program director at Human Rights Watch.
Doctors Without Borders/Medecins Sans Frontieres said Thursday in a statement on its website that patients from all religious and political backgrounds "continue to avoid seeking medical care in public hospitals due to perceived discrimination, harassment, and ill treatment."
The group suspended activities in Bahrain in March. "Since last summer, hundreds of patients have avoided going to public hospitals," said Bart Janssens, Medecins Sans Frontieres director of operations in Brussels.
There was no immediate response from the Bahrain government to a request for comment.
Further inflaming a number of the protesters was the precarious health of a jailed activist who has been on a hunger strike for more than two months.
Friday marked the 65th day without food for Abdulhadi al-Khawaja, 52.
Bahrain Information Authority International Counselor Abdul-Aziz bin Mubarak said that he was in stable condition and being administered fluids intravenously with his consent.
Al-Khawaja was arrested a year ago and is serving a life sentence for his role in anti-government protests that continue to roil Bahrain.
The United Nations has urged Bahrain to consider transferring the detainee, who holds Danish citizenship, to Denmark on humanitarian grounds.
But Mubarak said that the prisoner was being well cared for and that government officials had no plans to send him to Denmark. "We are providing him with all the care that he needs in order for his condition to be as stable as possible," Mubarak said.
Amnesty International said this week in a statement that al-Khawaja and 13 other prominent opposition activists are being held "solely for peacefully exercising their rights to freedom of expression and assembly."
The men have not advocated any violence, said Amnesty.
Relatives are concerned about his health. His daughter said al-Khawaja is having trouble breathing and is harassed by hospital staff and security guards.
Al-Khawaja was arrested in April 2011 for his role in anti-government protests that began a month earlier with demands for political reform and greater freedoms in the Sunni-ruled, Shiite-majority nation.
In June, Bahrain found him and seven other Shiite opposition activists guilty of plotting to overthrow the country's Sunni royal family.
He can appeal his life sentence during a hearing April 23, the government said.
CNN's Hamdi Alkhshali and Samira Said contributed to this report