"The Pentagon Press Office has been redesignated as a Sensitive Compartmented Information Facility" because speechwriters who "routinely handle classified material" work in the area, Acting Pentagon Press Secretary Joel Valdez said in a statement.

"As a result, journalists will no longer be permitted to enter the office space," he added.

The Pentagon began enacting new restrictions on journalists soon after President Donald Trump returned to office last year.

Eight media organizations including The New York Times, The Washington Post, CNN, NBC and NPR were forced to vacate their dedicated office spaces in the Pentagon, which said there was a need to create room for other -- predominantly conservative -- outlets.

The Pentagon later required remaining journalists to sign a new restrictive media policy in order to maintain access to the building.

US media including the Times and Fox News, and international news outlets such as AFP and Reuters, declined to do so, resulting in the stripping of their Pentagon credentials.

In response to a lawsuit brought by the Times, a US judge ruled in March that elements of the policy violated the US Constitution.

But the Pentagon responded with even tighter restrictions, announcing that it would close a press area called the Correspondents' Corridor and saying that all journalists accessing the building -- including those who signed the media policy -- would now require an escort.