Hundreds of people in restive Indian-administered Kashmir have been detained by police investigating a spate of targeted killings by suspected rebels, officials told AFP Sunday.

Tensions have been heightened in the Muslim-majority region -- which is contested by nuclear-armed neighbours India and Pakistan -- after New Delhi revoked Kashmir's semi-autonomy in August 2019 and brought it under direct rule.

Seven civilians were shot dead in six days last week, sparking public outrage in Kashmir and across the country. Politicians from all sides condemned the killings.

Nearly 500 residents suspected to have links with banned religious and militant groups were detained across the disputed territory following the shootings, a senior police officer told AFP on condition of anonymity.

"No stone will be left unturned to find the killers," the officer added.

A top anti-terrorism intelligence officer was sent by New Delhi to the region to head up the investigation.

India's counter-terrorism task force, the National Investigation Agency, summoned 40 schoolteachers in the main city of Srinagar for questioning on Sunday, officials said.

Authorities say at least 29 civilians -- including workers from pro-India political parties -- have been shot dead in Kashmir so far this year.

Twenty-two of them were Muslims, officials added.

The latest deaths were two teachers from the minority Sikh and Hindu communities, who were shot by gunmen at a government-run school in Srinagar on Thursday.

Another man was shot dead by security forces on Thursday when his car did not stop at a checkpoint.

Their deaths came two days after three civilians were killed in separate street shootings within 90 minutes.

A relatively new militant group The Resistance Front has claimed responsibility for the latest deaths and accused those killed of working for "occupier mercenary forces and occupier stooges".

The statements, issued only in English, were circulated in numerous WhatsApp groups. They could not be independently verified by AFP.

The killings have instilled fear among Kashmir's minorities, with local media reporting that many were fleeing the region.

On Saturday, Human Rights Watch called for the alleged perpetrators as well as Indian security forces accused of abuses including harassment, torture and extrajudicial killings to be held accountable for their actions.

"Kashmiris are caught in unending violence from attacks by militants and abuses by government authorities and security forces," HRW's South Asia director Meenakshi Ganguly said in a statement.

Rebel groups have been fighting Indian soldiers for over three decades, demanding independence for Kashmir or its merger with Pakistan.

The conflict has left tens of thousands of civilians, soldiers and rebels dead.