File Photo: Army Gen. Lloyd J. Austin III, commander of US Central Command, updates reporters at the Pentagon about the military campaign against Islamic State militants in Iraq, Friday, Oct. 17, 2014 (Photo: AP)
US Central Command suspended its Twitter page on Monday after a group declaring sympathy for Islamic State jihadists hacked its social media accounts and posted internal documents.
In an embarrassing propaganda jab at the American military, a black-and-white banner with the image of a hooded fighter and the words "CyberCaliphate" and "I love you ISIS" replaced Central Command's standard Twitter banner.
"We can confirm that the US Central Command Twitter and YouTube accounts were compromised earlier today. We are taking appropriate measures to address the matter," a defense official told AFP.
The CyberCaliphate "is already here, we are in your PCs, in each military base," the hackers wrote on the seized Twitter feed before it was taken down.
The military's powerful Central Command, located in Tampa, Florida, oversees the US-led air war against the group in Iraq and Syria and other American forces in the Middle East.
The hacking of CENTCOM's social media accounts came as President Barack Obama was delivering a speech on cyber security.
It was unclear if the hacking represented a genuine threat to sensitive computer networks, Pentagon officials said.
US officials said they were investigating the effect of the cyber hack but it appeared no classified documents were posted by the hackers.
The hacked Twitter feed posted a phone directory of officers, which looked to be slightly out of date, as well what appeared to be personal photos taken by troops and some power point slides related to North Korea and China.
US commanders and senior officials have previously said the IS group has shown a great acumen for propaganda and for promoting itself to potential jihadist recruits.