The Pentagon said Tuesday it had requested an investigation into a hacker group's reported cyber threat against a military base that is being used to hold a US soldier suspected of giving documents to WikiLeaks.

Pentagon spokesman Colonel David Lapan said the probe was requested after news that the hacker group called Anonymous was seeking to disrupt online activities at the Quantico, Virginia, base where Private Bradley Manning is incarcerated.

"The base at Quantico, including the brig, are aware of that and they have made law enforcement agencies aware of that as well," Lapan said.

The Financial Times reported that hackers known as "Anonymous," which had claimed credit for attacks supporting WikiLeaks in recent months, was seeking to disrupt communications at the US Marine base.

Manning, 23, has been held at the prison since July under a maximum security regimen because authorities say his escape would pose a risk to national security.

The army private faces numerous charges of stealing classified files and is suspected as the source of a trove of secret documents published on the WikiLeaks website in recent months, which have infuriated and embarrassed US officials.

US military authorities brought additional charges against Manning last week, accusing him of illegally downloading vast numbers of secret government files and "aiding the enemy."

His defense lawyers have filed a legal complaint over the conditions of his detention at Quantico, which include a "prevention of injury" watch, which his lawyer said includes being forced to sleep naked.

His supporters say the regimen is inhumane and has been deemed unnecessary by psychiatric experts.

The WikiLeaks website has yet to disclose its source for the US military and diplomatic documents published in recent months, but suspicion has focused on Manning, who worked as a low-ranking army intelligence analyst in Iraq.

Manning was arrested in May and authorities have yet to say when he will be put on trial. If found guilty, Manning faces up to 52 years in prison.

In December, the loose-knit group of hackers known as Anonymous staged cyber attacks on the websites of Visa, Mastercard, PayPal and others accusing them of withdrawing services to WikiLeaks.