SRINAGAR - At least 11 protesters died as crowds angered by the killing of a Kashmiri fighter clashed with armed police in Indian-held Kashmir on Saturday, torching buildings and blocking streets.

Demonstrators set fire to three police stations and two government buildings in towns south of Srinagar and dozens were injured on both sides, said two Indian police sources not authorised to talk to the press.

Three police had gone missing in the violence, and officers were forced to fire tear gas at the crowds and shoot their guns, said additional director general of Jammu and Kashmir police SM Sahai.

Protests erupted a day after security services shot dead Burhan Wani, a 22-year-old militant known for his calls to arms on social media and leader of Hizbul Mujahideen, one of a number of groups fighting Indian control of the Muslim-majority region.

Government forces fired tear gas canisters and live ammunition at protesters in several places.

The shootout came amid a rise in violence and separatist sentiment across the state, which has been at the centre of a strategic tussle between India and Pakistan for decades.

Sahai told reporters that several protesters were killed by government forces in "retaliatory action" and one drowned in a river as clashes intensified.

More 100 protesters with bullet injuries were brought into different hospitals, including 50 in a hospital in Srinagar, two health officials said.

Sahai said ninety government forces personnel were also injured during the clashes that spread across the disputed territory as protesters torched police stations and threw rocks at army camps in the south of the restive region.

"Six of them (the injured protesters) are in a critical condition," a staff member at a hospital in Anantnag told AFP, asking to remain anonymous. Authorities handed the body of Wani, viewed by locals as a hero since he joined the rebel group at the age of 15, over to his family early Saturday morning.

He was buried as tens of thousands attending the funeral chanted independence slogans and some fired pistol shots in his honour, witnesses said. "It was a sea of people shouting slogans in favour of freedom from India," one said.

Photographs appeared to show thousands attending Wani's funeral in his hometown of Tral, about 40 km south of Srinagar, despite restrictions on the movement of people and traffic ordered the night before.

Streets in Srinagar were mainly deserted except for hundreds of soldiers and police ordering people to stay indoors, but protests and clashes were reported from peripheries of the capital city. "Yes we have imposed a curfew, but of course his (Wani's) funeral was allowed," director general of police for the Indian-held region, K Rajendra told AFP.

Police said they halted traffic on the main highway connecting the state to the rest of India and officials said train services had been temporarily halted in the area. Mobile Internet services were blocked across some parts of the state and cell phone service was interrupted in others.

Authorities imposed a curfew in large parts of the territory. But thousands defied the restrictions as tensions intensified and clashes spread.

Wani, the son of a school headmaster, regularly posted video messages online, dressed in military fatigues and inviting young men to join his jihad. Kashmiri political leaders have called for a strike and three days of mourning.

Wani's death had sparked protests and clashes throughout the night Friday, with mosque loudspeakers blaring "Azadi" (freedom from Indian rule) in most areas, including the capital Srinagar.

"Aftr many yrs I hear slogans for 'Azadi' resonate from the mosque in my uptown Srinagar locality," former chief minister of the disputed state, Omar Abdullah, said on Twitter. "Kashmir's disaffected got a new icon y'day."

"Mark my words - Burhan's ability to recruit into militancy from the grave will far outstrip anything he could have done on social media," Abdullah said.

Resistance groups opposed to Indian rule have called for three days of mourning and a shutdown in the territory after Wani's killing.