Mortar shells fired from Afghanistan on Friday killed five people in Pakistan's South Waziristan tribal district, Pakistani officials said.
"The shells hit five people near Angoor Adda, around three kilometres (1.8 miles) from Afghanistan border, and killed them," said a Pakistani security official.
The identity of the victims was not immediately clear as two officials said they were local militants and another said they were still identifying the bodies.
"They were local militants who were coming towards Angoor Adda from Afghan border," said the security official on condition of anonymity because he was not authorised to speak to the media.
"There was a fire on Afghan forces a while before the mortar shells hit these people. They might have been attacked in retaliation," he added.
Afghanistan and Pakistan regularly accuse each other of staging shelling barrages across the border.