The US army had to take down its army.mil website after the Syrian Electronic Army compromised the website and posted messages on its Twitter account.
One of the messages on Twitter read: "Your commanders admit they are training the people they have sent you to die fighting."
US Brigadier general Malcolm Frost said: "After this came to our attention, the Army took appropriate preventive measures to ensure there was no breach of Army data by taking down the website temporarily."
The hacker group, who support President Bashar al-Assad, surfaced after the Syrian civil war broke out and has previously launched similar cyber attacks on the Washington Post and Associated Press Twitter feed.
Previously, the US Central Command had to shutter its YouTube and Twitter accounts after it fell victim to cyber vandalism when pro-Islamic State messages were posted on the sites.
Recently, the US Office of Personnel Management (OPM) also announced that its networks have been attacked and data of more than four million current and former federal employees have been affected.
The OPM attack was reportedly carried out by Chinese hackers.
