The US counter-intelligence official who led the Pentagon's review into the fallout from the WikiLeaks disclosures of state secrets told the Bradley Manning sentencing hearing on Wednesday that no instances were ever found of any individual killed by enemy forces as a result of having been named in the releases.

Brigadier general Robert Carr, a senior counter-intelligence officer who headed the Information Review Task Force that investigated the impact of WikiLeaks disclosures on behalf of the Defense Department, told a court at Fort Meade, Maryland, that they had uncovered no specific examples of anyone who had lost his or her life in reprisals that followed the publication of the disclosures on the internet. "I don't have a specific example," he said.

It has been one of the main criticisms of the WikiLeaks publications that they put lives at risk, particularly in Iran and Afghanistan. The admission by the Pentagon's chief investigator into the fallout from WikiLeaks that no such casualties were identified marks a significant undermining of such arguments.

Carr, who retired from active duty in 2011 and now works for the private defence firm Northrop Grumman, was the first witness called by the US government in the sentencing phase of the prosecution of the army private. Manning was on Tuesday found guilty of 20 counts offences relating to his transmission of US state secrets to WikiLeaks, carrying a maximum sentence of 136 years in military jail.

Carr initially toldl the judge presiding over the case, Colonel Denise Lind, that there had been an individual killed in Afghanistan as a result of the publication by WikiLeaks of the Afghan war logs that recorded military activities on the ground. "As a result of the Afghan logs I know of one individual killed – an Afghan national who had a relationship with the US government and the Taliban came out and said publicly that they had killed him as a result of him being associated with information in these logs," Carr said.

But under defence cross-examination Carr conceded that the victim's name had not be included in the war logs made public by WikiLeaks. Asked by Lind whether the individual who was killed was tied to the disclosures, Carr replied: "The Taliban killed him and tied him to the disclosures. We went back and looked for the name in the disclosures. The name of the individual killed was not in the disclosures."

On the basis of the witness's clarification, Lind sustained an objection from the defence and scrubbed from the official record any reference to the alleged killing by the Taliban.

Carr said that when his task force reviewed the Afghan war logs they found about 900 names of local nationals contained in the records. Many of those names were already of people who had died, and under cross-examination the witness said some could have been misspelled or mis-translated.

In the wake of the leaks, he said the Pentagon set up a warning system for any Afghan or Iraqi national whose co-operation with the US forces might put them in danger. A "duty to warn" was issued for actual informants who were providing intelligence to the US troops, and a lesser "duty to notify" was provided to local villagers who might be helpful on a less formal basis.

"If the adversary had more information about which people in the village were collaborating with US forces, there was a chance those folks could be at greater risk," Carr said. Under questioning from the prosecution, the witness said that disclosure of the war logs had damaged the US army's relationship with local nationals.

"Their interaction with our soldiers is critical. So that we can go into a village we need the police chief, the mayor, the civil leaders to work with us to build a civil society. The concern was if the names came out then they would back off from these interactions."

Lind reminded the court at the start of the hearing on Wednesday that Manning would have a total of 1,274 days cut from his eventual punishment. That includes 1,162 days for time served plus 112 days in compensation for the unlawful pre-trial punishment he received while held in solitary confinement at a military brig in Quantico, Virginia.

Both sides will use the sentencing phase, which amounts to a new, mini-trial, to influence the eventual punishment Manning receives.

The defence, when it begins its case in several days' time, will present mitigating evidence designed to soften the blow of the final sentence. Pre-trial hearings have indicated that Manning's lead counsel, David Coombs, is likely to raise the emotionally fragile state Manning was in at the time of the leaks, including conflicts over his gender.

In legal argument on Wednesday, Coombs accused the government of misleading him over the nature of the sentencing evidence it intended to present, and Major Ashden Fein for the prosecution countered that the defence was raising spurious objections at the last minute.

"It appears that the government is trying to put just about everything that ever happened at the foot of Pfc Manning," Coombs said.