US government monitored North Korean hackers since 2010
Is 'The Interview' the reason Sony Pictures was hacked? Sony Pictures

Sony Pictures is set to officially name North Korea as the source of a hacking attack that brought down the company's corporate network and leaked sensitive documents, according to sources close to the investigation.

The details of the announcement by Sony and security company Mandiant is still being confirmed, according to the tech website Re/code.

However, sources confirmed to the website that North Korea will be named as the source of the attack.

In November, Sony Pictures' film and TV studio unit were hacked and a raft of unreleased movies, including the film Fury which stars Brad Pitt, were released online.

North Korea has attempted to prevent Sony from releasing The Interview, a comedy film starring Seth Rogen and James Franco, which sees the CIA hire two reporters to assassinate the pariah state's leader, Kim Jong-un.

Other movies being shared illegally, following the hack, include Annie, Mr. Turner, Still Alice and To Write Love on Her Arms.

The leak also saw employee salary data and product plans released. North Korea has denied any involvement in the hack.

"The hostile forces are relating everything to the DPRK (North Korea)," said a North Korean government spokesman when asked about the country's involvement.

"I kindly advise you to just wait and see," he added.