Militants have stepped up attacks in India-held Kashmir (IHK) and police warned officers not to go home, amid a spike in violence in the contested region, after the army allegedly tied a man to the front of a jeep as a human shield.

Police have filed a case against the army over the incident, in which soldiers are accused of seizing a 24-year-old shawl weaver on April 9, strapping him to the front of their vehicle and then parading him through villages.

A video of the episode circulated widely on social media, in a reminder for some of alleged human rights abuses perpetrated by Indian security forces as they struggle to contain a separatist insurgency that is now in its 28th year.

Army spokesman Lieutenant Colonel Rajesh Kalia said the veracity of the video was being ascertained, adding, "Action will be taken against those found guilty of misconduct."

Protests last week followed a botched by-election in which at least eight people were killed.

Over the weekend two more videos circulated on social media showing workers of the ruling political party in Jammu and Kashmir renouncing mainstream politics, one of them beside a man wielding a gun.

Another, allegedly showing the killing of a 17-year-old by paramilitary officers during the April 9 by-election, has roused further anger. Reuters could not confirm the veracity of the videos.

IHK witnessed deadly protests after Burhan Wani, a well-known separatist, was killed last year.

Violence has declined since the early 2000s when thousands died each year, but disillusionment and anger against Indian rule remains widespread, and the separatist revolt is now largely homegrown.

Human shield

Farooq Ahmad Dar, a shawl weaver, was picked up by soldiers near the home of a relative after voting in the by-election, he told media. "Look at the fate of the stone-pelter," a soldier is saying over a loudspeaker, in the video.

"This is a phenomenon that has been going on for the last 27 years," Khurram Parvez, a leading Kashmiri human rights activist jailed last year, told Reuters.

"This is not the first human shield case. What is different now is that this case has been documented, thanks to social media.

"The treatment of Dar was "unlawful and unacceptable," rights group Amnesty International said in a statement.

The state's chief minister, Mehbooba Mufti, said police had registered a case against the local army unit.

The director general of police in the state on Sunday told officers to avoid visiting their own homes in South Kashmir after militants stormed at least four officers' houses.

Militants also shot dead a lawyer affiliated with an opposition political party, as well as a former counter-insurgency commander, police said on Sunday. A worker for the ruling party was killed in south Kashmir late on Saturday.