Border Security Force Director General Ajay Raj Sharma on Monday said a security lapse had resulted in a landmine blast on the Srinagar-Jammu national highway that blew up a bus carrying BSF jawans and their families.

Twenty-nine people were killed while six were injured in the attack, which he described as an act of cowardice.

"Those checking the area are humans who can err. There has been some lapse," he said.

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The place where the blast took place falls under the 8-km stretch on the highway, which is prone to militant attacks.

"Central Reserve Police Force officers will investigate the incident. We will draw lessons from it."

Sharma, who arrived in Srinagar on Sunday evening with Special Secretary (Jammu and Kashmir) B B Mishra, would submit a report on the incident to Union Home Minister Shivraj Patil on their return to Delhi.

Hizbul Mujahideen, which claimed responsibility, reportedly carried out the attack to avenge the elimination of its top leadership.