PESHAWAR, Pakistan (AP) -- A mortar shell meant to be fired in celebration of a wedding in a Pakistani tribal area exploded prematurely Saturday, killing at least 25 people, including the bridegroom and many of his relatives, officials said.

The blast occurred in the village of Korez, 180 miles southwest of the northeast Pakistan frontier city of Peshawar, in the tribal area of Orakzai.

During the wedding festivities, one of the groom's relatives tried to fire the mortar shell as a form of noisy celebration, but it went off early. Several people, including some children, were killed outright, and others died of their injuries at the local hospital, authorities said.

Members of Pakistan's tribes often fire small and heavy weapons in the air to celebrate weddings and other festive occasions.

The Orakzai area is largely governed by tribal elders, and Pakistan's central government holds little sway there. It is also home to a thriving black market in military-style weapons.