The hackers, who call themselves the Syrian Electronic Army (SEA) , say they targeted CENTCOM after US President Barack Obama announced a “decision to attack Syria with electronic warfare.”
In a message on its Twitter account on Friday, the group claimed to “have already successfully penetrated many central repositories.”
“In the coming days we will update you with specific details and hundreds of documents that the SEA has obtained,” the group said.
The group has also been linked to a number of high-profile cyber activities, including its more recent hack of Forbes magazine. 
Last month, the New York Times revealed that the United States was developing a battle plan against Syria that featured a sophisticated cyber attack on the Syrian military and the command structure of the Syrian government.
The US National Security Council met on February 21 to explore what one US official called “old and new options,” the report said, referring to a US plan in 2011, when the Pentagon and the US National Security Agency first examined the use of cyber arms against Syria. 
Caitlin Hayden, the spokeswoman for the National Security Council, said that in 2012 the US president “signed a classified presidential directive relating to cyber operations that establishes principles and processes so that cyber tools are integrated with the full array of national security tools.”