At least three soldiers and a civilian have been killed and 19 others injured by a car bomb in Indian-administered Kashmir, police say.
The blast occurred near a school in Srinagar, the state's summer capital. No children were hurt, reports say.
The Hizbul Mujahideen carried out the attack, a man claiming to be a spokesman of the militant group said.
About 40,000 people have been killed in fighting between Indian security forces and militants in the region since 1989.
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The BBC's Altaf Hussain in Srinagar says the explosion was caused by a car bomb in a high security area where most of the state's ministers and bureaucrats live.
Army spokesman Lt Col VK Batra said the car was being driven by a suicide bomber.
But a man claiming to be a spokesman of Hizbul Mujahideen said the bomb was detonated by remote control.
We could see at least one dead soldier whose head had been severed. Other civilians were lying in a pool of blood
Abdul Majid, eyewitness
In pictures: Kashmir attack
A senior police official, Haseeb Ahmed, told the Associated Press that no children were hurt inside the school.
"It was a devastating blast," Abdul Majid, an eyewitness, told the AFP news agency.
"We saw an army jeep thrown on to the footpath. We could see at least one dead soldier whose head had been severed. Other civilians were lying in a pool of blood."
This is the second car bomb explosion in Srinagar in the past month.
Nine Indian troops were killed and 15 wounded in an explosion - reportedly detonated remotely - outside a tourist site on 24 June.
Escalation
Violence has escalated in Indian-administered Kashmir after a period of relative calm following peace moves between India and Pakistan.
I am quite certain [Pakistani troops] know that the infiltration [of militants] is taking place
Lt Gen SS Dhillon,
Indian army commander
The peace moves are aimed at ending decades of dispute over Kashmir - a region both countries claim in its entirety.
India accuses Pakistan of sponsoring a violent uprising in Kashmir, a charge Islamabad denies.
India says that over a dozen militant groups, mostly based in Pakistan, have been fighting security forces in Jammu and Kashmir state since 1989 to carve out a separate homeland or merge the Himalayan region into Pakistan.
But Pakistan says it has only given diplomatic support to militant groups in the past and has now taken steps to ensure they no longer have bases in the country.
On Tuesday, India's new army commander in the state, Lt Gen SS Dhillon said Pakistani troops were aware of the infiltration of militants across the Line of Control that divides Kashmir.
"What active support they are giving to the infiltration, how much and to what extent they are helping are difficult for me to say. But I am quite certain that they know that the infiltration is taking place," he said.
Indian Prime Minister Manmohan Singh has warned that rising violence in Kashmir could jeopardise peace talks with Pakistan.
He was speaking in Washington hours after a bomb attack in Srinagar in Indian-administered Kashmir that killed three soldiers and a civilian.
The militant group, Hizbul Mujahideen, said it carried out the attack.
Delhi says Pakistani troops are not stopping militants from infiltrating into areas controlled by India.
Indian security forces say they have been engaged in a number of confrontations with militants in recent weeks.
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Kashmir dispute
Mr Singh told reporters in Washington on Wednesday that the development was "disturbing".
"I as the prime minister of a democracy cannot move ahead of Indian public opinion if acts of terrorism are not under control," he said.
"That certainly affects my ability to push forward the process of normalising our relations with Pakistan."
Mr Singh made a similar warning about the impact of public opinion on the peace process after gunmen attacked the disputed religious site at Ayodhya earlier this month.
Local police blamed the Lashkar-e-Toiba militant group for the attack.
Conflicting accounts
Wednesday's bomb in Srinagar went off near a school injuring 19 people as well as leaving four dead.
The BBC's Altaf Hussain in Srinagar says the explosion was caused by a car bomb in a high security area where most of the state's ministers and bureaucrats live.
Army spokesman, Lt Col VK Batra, said the car was being driven by a suicide bomber.
But a man claiming to be a spokesman of Hizbul Mujahideen said the bomb was detonated by remote control.
About 40,000 people have been killed in fighting between Indian security forces and militants in the region since 1989.
Escalation
Violence has escalated in Indian-administered Kashmir after a period of relative calm following peace moves between India and Pakistan.
The peace moves are aimed at ending decades of dispute over Kashmir - a region both countries claim in its entirety.
India accuses Pakistan of sponsoring a violent uprising in Kashmir, a charge Islamabad denies.
India says that over a dozen militant groups, mostly based in Pakistan, have been fighting security forces in Jammu and Kashmir state since 1989 to carve out a separate homeland or merge the Himalayan region into Pakistan.
But Pakistan says it has only given diplomatic support to militant groups in the past and has now taken steps to ensure they no longer have bases in the country.
On Tuesday, India's new army commander in the state, Lt Gen SS Dhillon, said Pakistani troops were aware of the infiltration of militants across the Line of Control that divides Kashmir.
"What active support they are giving to the infiltration, how much and to what extent they are helping are difficult for me to say. But I am quite certain that they know that the infiltration is taking place," he said.
