Pakistan ? A veteran U.N. official due to retire soon was shot dead along with a guard while resisting kidnappers Thursday at a northwest Pakistan refugee camp, the latest indication of the peril facing humanitarian workers aiding those uprooted by army offensives against the Taliban.

No one immediately claimed responsibility for the attack at Kacha Garhi, a camp on the outskirts of Peshawar city, but observers said it was likely the work of a criminal gang, and not Taliban militants. Overall security has deteriorated in Pakistan as the Taliban gained strength in the past decade, and kidnappings for ransom, among other crimes, have soared.

The attack occurred around the time Adm. Mike Mullen, chairman of the U.S. Joint Chiefs of Staff, visited a nearby camp as part of a trip to meet with Pakistani officials.

The slain U.N. worker was Zill-e-Usman, a Pakistani in charge of the U.N.’s relief efforts at the camp. The chief of the U.N. refugee agency in Pakistan, Guenet Guebre-Christos, said the 59-year-old Usman had worked for the U.N. for nearly 30 years and was set to retire. A U.N. statement said he left behind a wife and four children.