The US on Thursday condemned the terror attack in Jammu and Kashmir's Pulwama district and said it stands alongside India in defeating terrorism.

In one of the deadliest terror attacks in Jammu and Kashmir's three decades of militancy, a Jaish suicide bomber rammed an explosives-laden vehicle into a CRPF bus in Pulwama district, killing at least 39 personnel and leaving many critically wounded. 

"The US Mission in India strongly condemns today's terrorist attack in Jammu & Kashmir. We send our heartfelt condolences to the families of the victims," US Ambassador to India Kenneth Juster tweeted.

The US stands alongside India in confronting terror and defeating it, he said.

More than 2,500 Central Reserve Police Force personnel, many of them returning from leave to rejoin duty in the Valley, were travelling in the convoy of 78 vehicles when they were ambushed on the Srinagar-Jammu highway at Latoomode in Awantipora in south Kashmir around 3.15 pm.

The Pakistan-based Jaish-e-Mohammed terror group has claimed responsibility for the attack that took place about 20 km from Srinagar.