The United Nations plans to temporarily relocate some of its international staff outside of Pakistan for security reasons following a string of attacks that has killed at least 11 of its personnel in the country this year, the group said Thursday.

The move comes about two months after the U.N. decided to suspend long-term development work in volatile areas near the Afghan border. Both decisions could complicate international efforts to win hearts and minds in Pakistan, where a raging Taliban-led insurgency has killed over 500 people in the past two and a half months.

Around 20 percent of the U.N.'s expatriate workers will either leave the country for six months or be relocated to safer areas within Pakistan, spokeswoman Ishrat Rizvi said. The world body will reevaluate the security situation in six months to determine when the staff can return, she said.

"We will review programs and projects and we will see whether we need to bring back those international staff members and which programs are to resume," Rizvi told The Associated Press.

She declined to specify how many international employees work for the U.N. in the country or will be affected by the decision.

The U.N. announced in early November that it was suspending long-term development work in Pakistan's tribal areas and its Northwest Frontier Province. It said it would reduce the level of international staff in Pakistan and confine its work to emergency, humanitarian relief and security operations, and "any other essential operations as advised by the secretary-general."

The U.N. has continued to work with the Pakistani government to determine how to adjust its programs to focus on more urgent needs because of the deteriorating security situation, Rizvi said.

"We are focusing more on the more urgent programs and needs according to the government's priorities and needs," she said.

The U.N. has been deeply involved in helping Pakistan deal with refugee crises resulting from army offensives against militants. Its personnel have been targeted in a string of attacks, including a bombing in October of the World Food Program's office in Islamabad that killed five people.