Central Reserve Police Force (CRPF) personnel from 24 Battalion, stationed near the tunnel, detected the IED planted under a culvert near the tunnel last night, CRPF spokesman Sudhir Kumar told PTI.
He said the explosive device was detected at around 1210 Hours last night following which the Bomb Disposal Squad was called in.
Kumar said the bomb was later defused and a "major tragedy averted".
Jawahar tunnel is a key road link connecting Kashmir Valley with the rest of the country.