A U.S. army private charged with leaking classified material to the whistleblower website WikiLeaks had civilian help, a key figure in the case said Saturday.

The development, first reported in the New York Times, suggests an expansion of the government's investigation into leaks including more than 76,900 secret Afghanistan war records posted on WikiLeaks in the past week.

Army and FBI officials didn't immediately return calls and emails from The Associated Press asking if they are looking at possible civilian accomplices of the private, Bradley E. Manning, who's charged under military law with leaking classified material.

U.S. Pte. Bradley Manning, shown in this undated photo, has been charged with leaking U.S. military secrets to the WikiLeaks website. (Associated Press)

Adrian Lamo, the Sacramento, Calif.-based computer hacker who turned in Manning to military authorities in May, claimed in a telephone interview Saturday he had firsthand knowledge that someone helped Manning set up encryption software to send classified information to WikiLeaks.

Lamo, who's co-operating with investigators, wouldn't name the person but said the man was among a group of people in the Boston area who work with WikiLeaks. He said the man told him "he actually helped Private Manning set up the encryption software he used."

Lamo said the software enabled Manning to send classified data in small bits so that it would seem innocuous.

"It wouldn't look too much different from your average guy doing his banking online," Lamo said.

He said Manning sent the data to get the attention of WikiLeaks founder Julian Assange. Assange didn't immediately respond to an emailed query from AP about Lamo's claim.

Also on Saturday, a New York Times reporter who has been the newspaper's liaison with Assange dismissed Assange's claim that WikiLeaks had offered to let U.S. government officials go through leaked documents to ensure that no innocent people were identified.

Assange told the Australian Broadcasting Corp. in an interview that aired Thursday that the New York Times had acted as an intermediary and that the White House hadn't responded to the offer.

Times reporter Eric Schmitt told AP that on the night of July 23, at White House spokesman's Robert Gibbs' request, he relayed to Assange a White House request that WikiLeaks not publish information that could lead to people being physically harmed.

The next evening, Schmitt said, Assange replied in an email that WikiLeaks was withholding 15,000 documents for review. Schmitt said Assange wrote that WikiLeaks would consider recommendations made by the International Security Assistance Force "on the identification of innocents for this material if it is willing to provide reviewers."

Schmitt said he forwarded the email to White House officials and Times editors.

"I certainly didn't consider this a serious and realistic offer to the White House to vet any of the documents before they were to be posted, and I think it's ridiculous that Assange is portraying it that way now," Schmitt wrote to the AP.

On Friday, White House spokesman Tommy Vietor said it was "absolutely, unequivocally not true" that WikiLeaks had offered to let U.S. government officials go through the documents to make sure no innocent people were identified.

Manning is being held at the Quantico Marine Corps Base in northern Virginia, awaiting possible trial on 12 offences.

He is accused of leaking a helicopter cockpit video from Iraq that WikiLeaks posted in April, and a classified cable from the U.S. embassy in Reykjavik, Iceland, dated Jan. 13, 2010, that also has appeared on WikiLeaks.

Manning is also charged with illegally obtaining more than 150,000 classified State Department cables and leaking more than 50 of them. It's not clear from the charges, though, whether the allegedly diverted documents were those published on the WikiLeaks site.