A soldier was also martyred and three others badly injured during the retaliation.

According to our correspondent, over 50 militants attacked the checkpost earlier today but Pakistan army disposed off the attack and killed 20 of them and injured 25 others.

Army begun search operation in the area and the militants said to be afghan insurgents, sources said.

While no group immediately claimed responsibility for the attack.

Last November, the border checkpost was attacked by a US military helicopter, leading to the death of 24 soldiers.