Photo: The Canadian Press

At least 33 soldiers were killed and about 20 others wounded Thursday in a car bomb attack on a paramilitary convoy along a key highway in Indian-controlled Kashmir, security officials said. It was one of the deadliest car bombings in the disputed region's history.

Officials said a local Kashmiri militant rammed an explosive-laden van into the convoy, targeting a bus carrying at least 35 soldiers.

Senior police officer Muneer Ahmed Khan said the attack occurred as the convoy reached southern Lethpora town on the outskirts of the main city of Srinagar. He said the bus was destroyed and at least five other vehicles were damaged by the blast.

Sanjay Sharma, a spokesman for India's paramilitary Central Reserve Police Force, said many of the injured were in critical condition. "The blast was so powerful that one cannot recognize whether the vehicle was a bus or a truck. Just pieces of mangled steel remain of the vehicle," he said.

Videos circulated by local news groups showed ambulances rushing to the site and people running as smoke billowed from the damaged vehicles. Debris and body parts littered the road.

Authorities closed the highway following the blast. Police officer Khan said soldiers and counterinsurgency police reinforcements were deployed in the area and were conducting searches.

The Greater Kashmir newspaper reported that militant group Jaish-e-Mohammed claimed responsibility for the attack.

A pre-recorded nine-minute video, circulated on social media sites, showed the purported attacker in combat clothes and surrounded by guns and grenades.

Later Thursday, thousands of people, chanting slogans such "Go India, go back," marched to the militant's village in solidarity. Government forces tried to stop the people from gathering, leading to clashes as groups of young people hurled stones at the troops, who fired tear gas. No injuries were immediately reported there.

Kashmir Gov. Satya Pal Malik accused Pakistan of being behind the attack. "Visibly it seems to be guided from across the border as Jaish-e-Mohammed has claimed responsibility," Malik said in a statement. "Such actions will not deter the resolve of our security forces ... we will finish these inimical forces to the last."

Indian Prime Minister Narendra Modi condemned the attack in a tweet Thursday evening. "I strongly condemn this dastardly attack. The sacrifices of our brave security personnel shall not go in vain," he said.

The Pakistan Foreign Ministry in a statement in Islamabad said the attack in Pulwama "is a matter of grave concern."

"We have always condemned acts of violence anywhere in the world," the statement said. "We strongly reject any insinuation by elements in the Indian media and government that seek to link the attack to Pakistan without investigations."

The White House condemned the attack and said it strengthened U.S. resolve to bolster counterterrorism co-operation with India. "The United States calls on Pakistan to end immediately the support and safe haven provided to all terrorist groups operating on its soil, whose only goal is to sow chaos, violence, and terror in the region," the statement from the press secretary's office said.