OrbitalDawn
Ulysses Everett McGill
http://www.bbc.com/news/world-us-canada-30785232
US Central Command's Twitter account appears to have been hacked by a group claiming to back Islamic State.
One message said: "American soldiers, we are coming, watch your back."
It was signed by Isis, another name for the Islamic State. Some internal military documents also appeared on the Centcom Twitter feed.
US Centcom told the BBC it was preparing a statement. The Twitter account was later taken down so no tweets could be viewed.
The hack happened as President Barack Obama was preparing a speech on cybersecurity.
Subsequent posts on the Centcom Twitter account said: "Pentagon Networks Hacked! China Scenarios" and "Pentagon Networks Hacked. Korean Scenarios."
Some of the documents posted appeared to list names and phone numbers of members of the military as well as PowerPoint slides and maps.
The Centcom YouTube account was also hacked.
American and coalition war planes have been undertaking air strikes against IS in Iraq and Syria.