A US State Department official says the 250,000 diplomatic cables that soldier Bradley Manning disclosed through WikiLeaks hurt the department's ability to advance human rights because some foreign citizens were endangered and some activists became reluctant to seek US help.
Acting Assistant Secretary Michael Kozak testified on Friday at Manning's sentencing hearing.
Prosecutors are trying to show that the leaks harmed US interests. Manning has said he leaked the material to expose wrongdoing by the military and US diplomats.
Manning faces up to 136 years in prison for leaking classified information to the anti-secrecy group while working as an intelligence analyst in Iraq in 2010.
The 25-year-old was convicted on Tuesday of 20 of 22 counts, including Espionage Act violations, theft and computer fraud. He was acquitted of the most serious charge, aiding the enemy.
Kozak said the cables identified people who had worked with the United States, putting them at risk of death, violence or incarceration. He said the department helped some of those people relocate.
"We had a moral obligation" to protect people who had spoken to diplomats in confidence, Kozak said.
He declined to say publicly how many people his working group determined to be at risk.
He said he would provide the number in a session closed to spectators and reporters that followed his open-court testimony. Prosecutors requested the closed session to protect classified information.
Kozak said the greatest damage to State Department human-rights efforts was a "chilling effect" on foreign activists seeking US help.
"They can't be sure now whether what they say to us is going to remain confidential or whether it's going to be broadcast around," he said.
