The army said many of the refugees left their homes in the northwestern region of North Waziristan, and are in camps in nearby Khyber-Pakhtunkhwa.
"Government is with (the evacuees) in these hard times and they will be taken care of," said Pakistani President Nawaz Sharif, who met with government ministers Tuesday to discuss the situation.
Trucks were sent to North Waziristan to collect displaced people, and food and cooking oil was provided. The country's National Disaster Management Authority said it counted 455,590 people who have fled, 191,897 of whom are children.
The attacks on tribal areas in North Waziristan -- a loosely-governed region near the border with Afghanistan used as a base of operation by Islamist movements -- began June 15 and include heavy air assaults. Defense Minister Khawaja Asif said they are meant to "finish off" local militants "once and for all."