A suicide car bomber on Thursday crashed into a bus carrying Indian police officers in Kashmir, killing at least 33 in one of the deadliest attacks on security forces in the region in almost two decades.
The attack is likely to raise tensions once more between India and Pakistan in the disputed region.
The Pakistan-based Islamist militant group Jaish-e-Mohammad, or JeM, claimed responsibility for the attack on Kashmir's main highway, the BBC reported.
An official said the death toll could increase because dozens of others were "critically injured" in the attack on a convoy of the Central Reserve Police Force.
India's Prime Minister Narendra Modi described the attack as "despicable" and "dastardly."
He tweeted: "Attack on CRPF personnel in Pulwama is despicable. I strongly condemn this dastardly attack. The sacrifices of our brave security personnel shall not go in vain. The entire nation stands shoulder to shoulder with the families of the brave martyrs. May the injured recover quickly."
Two former chief ministers of the state, Omar Abdullah and Mehbooba Mufti, also tweeted about the attack.
"Terrible news coming from the valley. A number of CRPF soldiers are reported to have been killed & injured in an IED blast. I condemn this attack in the strongest possible terms. My prayers for the injured & condolences to the families of the bereaved. #Kashmir," Abdullah tweeted.
Mufti wrote: "Disturbing news coming in from #awantipura. Twelve of our security personnel have been martyred and several have been injured. No words are enough to condemn the gruesome terror attack. How many more lives will be snuffed out before this madness ends?"
Kashmir is a Muslim-majority region that has been at the heart of decades of hostility between India and Pakistan. Each claims the entire area as theirs but only control parts of it.
The two countries have fought multiple wars since independence from Britain in 1947.
Prior to Thursday's bombing, the deadliest attack on Indian security forces in Kashmir this century came in 2002, when militants killed at least 31 people at an army base in Kaluchak.