Hackers purporting to be members or supporters of the Islamic State militant group have hacked social media accounts that belong to the US Central Command (Centcom).

An array of internal military documents and messages from the hackers appeared on Centcom's Twitter account Monday, while previously released Islamic State propaganda videos also appeared on the its official YouTube account.

Centcom confirmed that its Twitter account was "compromised" today in a statement, and said it "is taking appropriate measures to address the matter."

The hack occurred as President Barack Obama prepared to deliver a speech on cybersecurity, the BBC reported.

The perpetrators changed the profile and background of Centcom's Twitter account to show a masked figure with the phrases "I love you ISIS" and "cybercaliphate."

The Twitter account has since been shut down.

One message read "American soldiers, we are coming, watch your back!" next to what appears to be a list of the names and phone numbers of military personnel. Another warned: "We won't stop! We know everything about you, your wives and children."

The hackers allegedly posted a note to Pastebin explaining their reasons for the attack.

"In the name of Allah, the Most Gracious, the Most Merciful, the CyberCaliphate under the auspices of ISIS continues its CyberJihad," the message said. "While the US and its satellites kill our brothers in Syria, Iraq and Afghanistan we broke into your networks and personal devices and know everything about you.

"You'll see no mercy infidels," they wrote. "ISIS is already here, we are in your PCs, in each military base. With Allah's permission we are in CENTCOM now. We won't stop! We know everything about you, your wives and children. US soldiers! We're watching you!"

Two unidentified defense officials told Reuters that while the hack was embarrassing, it did not appear to be a major security threat.

It also appears that most of the "leaked" documents posted to the Centcom Twitter account and featured on Pastebin are already publically available elsewhere and can be accessed through a simple online search. Two diagrams labeled as tactical operations scenarios in China and North Korea look to have be taken from a presentation at the Lincoln Library, the Massachusetts Institute of Technology's think tank.

It is not clear whether the attacks were perpetrated by the same "CyberCaliphate" group that last week took over the Twitter feeds of the Albuquerque Journal newspaper and CBS' Maryland affiliate WBOC-TV on the same day. Identical "I love you ISIS" slogans and images of a figure wearing a kaffiyeh appeared on both accounts on January 6.

Centcom is responsible for planning and conducting US military operations in much of the Middle East and South Asia, including Iraq and Afghanistan_._