"This is a new way of infiltration," DIG Jammu Frontiers NS Jamwal said.
Jamwal, visited the spot for on spot assessments and went inside the tunnel along with DIG BSF J S Oberoi.
Speaking to reporters, Jamwal said the use of oxygen pipes inside the tunnel indicated that the tunnel had been dug with "proper planning and in a sophisticated way."
"As the militants had been unable to enter into this side through the border even by cutting fencing, a new technique has been used from across the border by digging underground tunnel to facilitate infiltration of militants," he said, adding exit of the tunnel has not been detected so far.
"The tunnel was part of a very deliberate attempt, executed through proper planning including the use of oxygen," Jamwal said, adding "it was yet to be ascertained as to how long the tunnel had gone into Pakistan".
BSF has not asked for a flag meeting with the Rangers so far. "We would complete our task of detecting exact length of tunnel including its exit route," he added.
BSF troops are using more dozers and men to find out the origin of the tunnel towards the Indo-Pak border.
"The operation is going on in full swing. More dozers and men are working uncover the tunnel into India from Pakistan. It will take some time to dug the entire tunnel," a senior BSF officer told PTI.
A team of senior officers from New Delhi will visit the spot to have a look at the cross-border tunnel.
Authorities had yesterday detected the 400-meter tunnel into India from Pakistan along Indo-Pak Border in Samba district.
The tunnel was detected after an area caved in a straight line at two three places due to rains near Chillayari Border Out Post (BoP) of BSF along International Border (IB) in Samba sector.
It was discovered accidentally by a farmer of Chachwal village of Samba.
