The attack, carried out from the Khost province of Afghanistan, also sees 10 attackers killed in retaliatory firing.
Scores of armed tribesmen assemble to join the security forces on border, say Kurram Agency govt officials.
JI's long march is aimed at exerting pressure on the federal government to revoke the Frontier Crimes Regulation.
Former prime minister says he is appearing before the courts out of respect for the judiciary.
Cross-border attack came from Afghanistan's Khost province as FC personnel were constructing a wall along the border.
Damage to property but no casualties reported, says local political administration.