At least 11 protesters died as crowds angered by the killing of a separatist militant clashed with armed police in India's Jammu and Kashmir state on Saturday, torching buildings and blocking streets, security officials said.

Police sources told Reuters that demonstrators set fire to three police stations and two government buildings in towns south of the state's summer capital of Srinagar, and three officers had gone missing in the violence.

Mirwaiz Umar Farooq, a separatist political leader, accused police of using excessive force and questioned their version of events.

The 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. He led Hizb-ul Mujahideen, prominent among the groups fighting Indian control of the Muslim-majority region.

His death 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.

Photographs appeared to show thousands attending Wani's funeral in his hometown of Tral, about 40 km (25 miles) south of Srinagar, despite restrictions on the movement of people and traffic ordered the night before.

"Unruly mobs attacked security forces," additional director general of Jammu and Kashmir police, SM Sahai said. "The violent incidents of arson and stone pelting were reported from several parts of Kashmir."

Some of the crowds tried to enter security installations and managed to steal weapons from one police station that they used to shoot at officers, Sahai added.

He put the death count at eight but two other officers, who asked not to named as they were not authorised to talk to the press, said three more people had died from their injuries.

Sahai said 96 security personnel had been injured during the day's violence alongside, the two police sources added, more than 60 protestors.

Farooq, the head of a faction of the All Parties Hurriyat Conference separatist alliance, accused police of brutish tactics. "The intention of police and Indian armed forces is always to shoot to kill and not disperse mobs by using non-lethal means," he said.

He said that "maybe at one place the people attacked a police station".

Farooq was one of a number of separatist leaders that authorities placed under house detention after Wani's death, and did not take part in any of the rallies.

India's minister for home affairs, Rajnath Singh, released a statement on Twitter on Saturday night asking for calm.

Jammu and Kashmir's former chief minister, Omar Abdullah, said Wani had now become a "new icon" for disaffected people in the state.

"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 on Twitter.

Shops, banks and other offices were closed in Srinagar, as paramilitary troops patrolled the streets outside.

Police said they halted traffic on the main highway connecting the state to the rest of India after disruptions by protestors 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.

Wani, the son of a school headmaster, regularly posted video messages online, dressed in military fatigues and inviting young men to join his jihad.

Separatist political leaders have called for a strike and three days of mourning.-Reuters