The bomb-making material was discovered during an operation in Momand Dara district of the southern province of Nangarhar on Sunday.
A spokesman for the governor of Nangarhar confirmed that intelligence officers found nearly eight tonnes of the chemical “brought for insurgent activities” and hidden under sacks of vegetables on the truck at Torkham border crossing.
Militant groups frequently use explosive materials for roadside bombings and car bomb attacks to target Afghan security personnel. However, most of the time ordinary civilians are targeted.
Pakistan and Afghanistan frequently accuse each other of harboring terrorists planning cross-border attacks.
The Afghan capital, Kabul, and several other cities have witnessed the deadliest bomb attacks over the past few months.
In May last year, a massive truck bomb struck the capital and killed more than 150 people.
Separately, Taliban militants stormed a security checkpoint on Saturday night. Five policemen were killed.
The deadly assaults have been carried out in spite of the fact that Taliban have agreed to a ceasefire with the Afghan government for Eid al-Fitr, which marks the end of the Muslim fasting month of Ramadan.