A Twitter account belonging to the US Army's Central Command has been hacked by individuals claiming to be ISIS sympatisers.

The Twitter account has been taken over by users who say they're waging a "cyber-Jihad" on the United States.

The account has also posted what appear to be classified or sensitive US military documents, including personal details of many senior military officers.

The unit's YouTube account also appears to have been hacked, and now contains two videos showing Jihadist messages.

American soldiers, we are coming, watch your back," the feed said on Monday.

"In the name of Allah, the Most Gracious, the Most Merciful, the CyberCaliphate continues its CyberJihad."

Images were also posted showing documents containing the contact details of current and retired military officers, including home addresses and email accounts.

"ISIS is already here, we are in your PCs, in each military base... we won't stop! We know everything about you, your wives and children," one post said.

The hackers also posted what appeared to be military plans associated with China as well as information on North Korea.

The Twitter account was later taken down. Centcom's YouTube account was also suspended on Monday.

Pentagon spokesman Army Colonel Steve Warren said the Defense Department viewed the hack "as little more than a prank, or as vandalism".

"It's inconvenient, it's an annoyance but in no way is any sensitive or classified information compromised," Col Warren told a press briefing.

The White House said it was monitoring the incident and that it took the hack "seriously".

Press Secretary Josh Earnest added a "note of caution", however, saying there is a "significant difference between what is a large data breach and the hacking of a Twitter account".

A Pentagon official told Reuters the hack was an embarrassment but did not appear to be a security threat.

The hack occurred as President Barack Obama outlined new proposals on Monday aimed at protecting the US from cybersecurity threats.

The proposals come in the wake of recent high-profile hacking incidents including one against Sony Pictures that US officials have blamed on North Korea.

Screengrab of @CENTCOM Twitter feed in the aftermath of the hack Image: Twitter