"The militants used to regroup and prepare attacks on security forces and take refuge at these compounds, so security forces targeted them," Arshad said, calling the compounds a "staging post."
A Reuters reporter in Miranshah had earlier seen eight helicopters gunships heading in the direction of Daygan.
A doctor in Miranshah said his hospital received three wounded people, including two children.
Witnesses there said the helicopters destroyed three houses. They also said the army was using mortars and artillery.
"As soon as firing began we ran out and during that a bomb hit our house," Attaullah Jan, one of the wounded, said from a hospital bed.
An anonymous army official said that fighting continued for up to seven hours after the operation began.
North Waziristan is seen as a hotbed of support for the Taliban and al-Qaeda, and an army offensive has been anticipated since fighters abandoned, last month, a peace pact struck with the government in September.
There have been several clashes between Pakistani troops and fighters over the past few weeks as the army reinforced checkpoints and carried out more patrols.
Fighters have struck back with a series of attacks, including suicide bombings, in Waziristan and elsewhere in the North West Frontier Province.
More than 200 people have been killed in bomb attacks and clashes since trouble broke out at the Red Mosque in early July.