David House said the only information he gave the grand jury in the WikiLeaks case was his name and address.

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Alexandria, Virginia (CNN) -- A friend and leading supporter of WikiLeaks suspect Bradley Manning said Wednesday he refused to testify before a grand jury, citing his Fifth Amendment rights against self-incrimination.

David House, one of the founding members of the Bradley Manning Support Network, told reporters after his hourlong court appearance the only information he gave the grand jury was his name and address.

Army Pvt. Bradley Manning is accused of leaking classified thousands of U.S. military and State Department documents to the whistleblower WikiLeaks website.

House said the grand jury was becoming "Nixonian," in that its intent is to "increase the climate of fear ... surrounding WikiLeaks and Bradley Manning."

"In my opinion, this is just another step in the government's ongoing investigation, a very ham-fisted investigation, centered around the Cambridge, Massachusetts, area," House said.

House is among the first of a series of Boston area residents scheduled to testify before the grand jury.

Manning has been held for 11 months, since March at the Joint Regional Correctional Facility at Fort Leavenworth, Kansas.

Initially he was held in maximum confinement in the brig at Quantico Marine Base in Virginia where critics, including House, said he was being mistreated.

House, who was one of the few visitors to see Manning in Quantico, told CNN in February that Manning seemed "frazzled." He said Manning was "sometimes simply catatonic, unable to have conversations about anything, really."

The Pentagon denies allegations that Manning has been mistreated. House said he flew to court from Boston at the U.S. government's expense.