"The UN will reduce the level of international staff in the country and confine its work to emergency, humanitarian relief, and security operations, and also any other essential operations as advised by the secretary-general," The Dawn quoted a UN statement, as saying.
The UN decision comes amid a recent wave of terrorist attacks that killed some 250 people last month.
A total of eleven UN staff have been killed in attacks in Pakistan this year.
"We have had 11 of our colleagues killed because of the security situation...All of the decisions are being made in light of that," UN spokeswoman Amena Kamaal said.
The staff that remains in the country will be assigned additional security, she said. (ANI)