The explosion targeting a convoy of the Central Reserve Police Force (CRPF) was heard from several miles away, according to witnesses.
Television images showed a mangled car amid rubble and snow around the site. Reuters photos showed tens of policemen surveying damaged vehicles and one policeman was seen carrying a plastic cover with guns inside.
The death toll stood at 44, a senior police official said.
The Central Reserve Force Police is a paramilitary organization that is working with the Indian military to quell the 30-year insurgency in Kashmir.
“I strongly condemn this dastardly attack. The sacrifices of our brave security personnel shall not go in vain,” Prime Minister Narendra Modi said in a tweet.
Indian forces have sporadically battled Islamist militants in mountainous Kashmir since an armed revolt in 1989 in which tens of thousands were killed, but car bombings are rare.
A video circulating on social media on Thursday purportedly featured the suicide bomber, and showed a young man holding a gun and threatening more attacks. Reuters was not able to independently verify the authenticity of the video.
The Indian foreign ministry accused the Pakistani government of giving the militant group Jaish a free run in Pakistan, saying it has allowed the group’s leader, Masood Azhar, “to operate and expand his terror infrastructure in territories under the control of Pakistan and to carry out attacks in India and elsewhere with impunity”.
The last major attack in Kashmir was in 2016 when militants raided an Indian army camp in Uri, killing 20 soldiers. Slideshow (11 Images)
Tension with Pakistan rose after that incident when New Delhi said the attackers had come from Pakistan to stage the assault. Pakistan denied any involvement.
The attack could put Modi, who faces a general election due by May, under political pressure to act against the militants and Pakistan.
Randeep Singh Surjewala, a spokesman for the main opposition Congress party, accused Modi of compromising on security. Former Air Force officer charged with spying
“Zero political action & Zero policy to tackle terror has led to an alarming security situation,” Surjewala said in one of a series of tweets.
Kanwal Sibal, a former top diplomat, said a diplomatic response from India would not be enough.
“They will have to do something otherwise I think it will be very difficult for government to absorb this blow and be seen to be doing nothing,” Sibal told Reuters.
The Jaish-e-Mohammad group is one of the most powerful militant groups operating in Kashmir. It was blamed for a 2001 attack on the Indian parliament that led to India deploying its military on the border with Pakistan.
In a statement carried by GNS news agency, a spokesman for the group said dozens of security force vehicles were destroyed in the attack.
Arun Jaitley, a senior minister in Modi’s cabinet, said India would retaliate, tweeting that “terrorists will be given unforgettable lesson for their heinous act”.
The U.S. ambassador to India, Ken Juster, condemned the attack, saying in a tweet that Washington stands alongside India in confronting terror and defeating it”.