Chief military spokesman Maj Gen Athar Abbas said claims by Afghan authorities were incorrect.
He said there had been five "major attacks" launched from Afghanistan that had killed 55 Pakistani security personnel in a month.
"This is not true. No rounds have been fired into Afghanistan. In the last one month, there have been five major attacks from the Afghan side of the border, (during which) 250-300 terrorists crossed over and assaulted our border posts," Abbas said in an SMS message sent to the media.
Militants from Afghanistan entered Dir district in Pakistan's northwest, Mohmand and Bajaur tribal regions, killing 55 paramilitary and local militia personnel and injuring 80 more, he said.
"The fleeing militants were engaged by the security forces and a few accidental rounds going across cannot be ruled out," Abbas said.
A statement issued by the Afghan presidential palace on Jun 26 said that Pakistani forces fired 470 rockets into Afghanistan's border regions.
The statement said 36 people, including 12 children, had died after being hit by the rockets.
Afghan officials said the rockets landed in the eastern Kunar and Nangrahar provinces.