(CNN) -- Police in Bahrain clashed Monday with opposition protesters and mourners attending the funeral of a demonstrator killed over the weekend, witnesses said.
Thousands of people gathered in the village of al-Bilad al-Qadeem to mourn Salah Abbas Habib Musa, whose body was found on a farm outside Manama early Saturday, day after he took part in a demonstration that was broken up by security forces, according to opposition groups. The mourners split into two groups, with some continuing to march toward a main square in the capital and the others heading toward the burial site, said Said Yousif of the Bahrain Center for Human Rights.
Yousif said police descended on the mourners and fired tear gas, flash-bang grenades and birdshot. The other group of protesters responded by throwing rocks and gas bombs, Yousif said.
The Ministry of Interior confirmed the clashes, saying in a Twitter post that "rioters blocked roads & committed acts of vandalism" before "police restored order."
"We have always said it before: The police would only engage is (when) commercial areas are blocked, lives are risked, or protesters resort to violence," said Fahad Binali, spokesman for the Information Affairs Authority. "That is the only grounds for police to do that, so allegations of police force acting arbitrarily have been found to be baseless many times."
Bahrain's leading opposition party, Al-Wefaq, said Habib suffered a neck fracture, wounds from birdshot, bruises to his hand and leg, and severe burns to his chest and stomach. The official cause of death on his death certificate, released by Al-Wefaq, was listed as internal bleeding and gunshot wounds.
The clashes come amid escalating unrest as anti-government protesters demand political reform and greater freedoms for Shiites.
Also Monday, a scheduled hearing where a Bahraini dissident on hunger strike could have appealed his life sentence was adjourned until April 30. Abdulhadi al-Khawaja was arrested in April 2011 for his role in anti-government protests that began a month earlier.
In June, Bahrain found him and seven other Shiite opposition activists guilty of plotting to overthrow the country's royal family.
Al-Khawaja has been on a hunger strike for more than two months. He was in stable condition, a Bahraini government spokesman said over the weekend.
On Monday, opposition members called for a sit-in protest in front of the court building, according to Al-Wefaq.
Bahrain's interior ministry would not authorize the protest, saying "it will disrupt the traffic and security in the area."
Al-Khawaja was not in court Monday, and the lawyer who would have handled the appeal dealt with other cases instead.
On Sunday, Denmark's ambassador met with al-Khawaja, who once lived in the country and holds Danish citizenship. The Danish government has asked that Bahrain turn him over; Bahraini officials have refused.
Meanwhile, crew members from Britain's Channel 4 News were released Monday after they were arrested while covering the unrest surrounding the Bahrain Grand Prix a day earlier.
Reporter Jonathan Miller, his team and his local driver were taken into custody on the day of the race, which took place despite days of protests by democracy campaigners in the Gulf state.
"In common with other foreign media, Channel 4 News was denied journalist visas and worked without accreditation during the grand prix," the agency said in a statement.
Bahraini Foreign Minister Khalid Alkhalifa responded via Twitter, saying that working without accreditation is "not acceptable. Laws of the land should be respected."
Channel 4 expressed concern for the local driver, "who was arrested and assaulted before being separated from them. When last seen he appeared to be bleeding from slashes to his arms."
On Monday morning, Miller said in a Twitter message that he'd "been released with my crew. Breakneck drive to Bahrain airport in police van. Being deported now." The foreign affairs correspondent wrote that police "refused to give us back our cameras and computers."
The driver, as well as an activist who was with Miller, were also eventually released, Miller tweeted.
Bahrain's interior ministry announced on Twitter that an investigation has been launched "into allegations by deported UK journalists about attack on driver."
Days of escalating government protests failed to halt the Bahrain Grand Prix, which took place even as nearby streets were blocked with burning tires and trash.
Anti-government protesters had called the race a publicity stunt by the country's rulers to make the nation appear more unified.
Nabeel Rajab, an opposition demonstrator, said protests were not against the Formula One race itself.
"We are just against the government or the oppressive ruling elite using that as PR," Rajab said.
A report by Amnesty International last week said promised reforms in Bahrain are inadequate and fail to provide justice for victims of human rights violations.
CNN's Peter Wilkinson, Samira Said, Fred Pleitgen, Saad Abedine and Salma Abdelaziz contributed to this report.