wo MIT-educated friends of arrested US Army intelligence analyst, Bradley Manning, a suspect in the WikiLeaks case, gave encryption software and taught him how to use it, according to media reports.

Adrian Lamo, the former computer hacker who tipped off US federal authorities to WikiLeaks suspect Manning, says two men in the Boston area, have told him in phone conversations that they assisted the 22-year-old Army private, suspected to be behind the biggest leak in US military history of classified documents on the war in Afghanistan.

Lamo said both men attend the Massachusetts Institute of Technology (MIT), but he refused to identify them because, he said, at least one of them has threatened him.

One of these men allegedly told Lamo they gave encryption software to Manning and taught the Army private how to use it, Lamo was quoted as saying by CNN.

Manning, an Army intelligence analyst, is being held in solitary confinement at a Virginia detention facility.

Manning was arrested in Baghdad in May and charged earlier this month with multiple counts of mishandling and leaking classified data, after Lamo turned him in.

He is charged with leaking an airstrike video that the whistleblower website WikiLeaks published in April, and Pentagon officials say he is the prime suspect in last week's disclosure of some 75,000 secret US military field reports from the war in Afghanistan to the site.

Lamo claimed both men are working for WikiLeaks. Also, both men are Facebook friends with Lamo and Manning, and at least one continues to post Facebook messages on Lamo's wall, the former hacker said.

Asked for comment about Lamo's allegation that men working for WikiLeaks assisted Manning, WikiLeaks responded in an e-mail: "As a matter of policy, we do not discuss any matters to do with allegations relating to the identity of sources."

The New York Times reported on Saturday that Army investigators looking into the document leak have expanded their inquiry to include friends and associates who may have helped Manning.

Specifically, the Times spoke to two civilians interviewed in recent weeks by the Army's criminal division, who said that investigators apparently believed that the friends, who include students from MIT and Boston University, might have connections to WikiLeaks.

The Boston Globe interviewed a recent MIT graduate who it said acknowledged that he met Manning in January and exchanged as many as 10 e-mails with him about security issues.

But the individual "adamantly" denied any role in the document leak, the Globe reported.

A spokeswoman for MIT, Patti Richards, said: "We are monitoring the situation closely, but are not commenting at this time.