At least 40 Indian paramilitary soldiers were killed on Thursday in Kashmir in the deadliest attack on government forces there since 2002, police said.
Reports suggest that the vehicle used by the assailant was carrying more than 350 kg of explosives.
Local media reports said the Pakistan-based Jaish-e-Mohammed Islamist group claimed responsibility.
A spokesman for the group told a local news agency that the "suicide attack" was carried out by Aadil Ahmad, alias Waqas Commando, a known militant from the area.
An Indian Home Ministry official said the attackers triggered the car bomb while 78 vehicles with over 2,500 CRPF men were on the Srinagar-Jammu highway.
The injured have been moved to the army base hospital in Srinagar, 20 km from the attack site.
"The sacrifices of our brave security personnel shall not go in vain," Indian Prime Minister Prime Minister Narendra Modi tweeted, calling the attack "despicable".
Australian Prime Minister Scott Morrison and Opposition Leader, Bill Shorten have condemned the attack.
"We convey our deepest condolences to the families of the victims, and all those injured. Our thoughts are with my friend Prime Minister @narendramodi and the Indian people," Mr Morrison tweeted on Friday.
