Hackers have shut down the United States Army's official website apparently in protest against Washington's support for the militants fighting against the Syrian government, Press TV reported.
The US forces official page, army.mil, was not accessible following the hack on Monday.
A Twitter page, called Syrian Electronic Army, said it was behind the move in a tweet.
It released an image showing a popup message announcing the move was carried out by the group.
"Today an element of the Army.mil service provider's content was compromised," said US Army Brigadier General Malcolm Frost. "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."
According to army officials, the attack did not affect any other pages belonging to the army.
Earlier, the official Facebook page of Fort Bragg, N.C., home of the US Army airborne and special operations forces, told its followers to "Avoid using www.army.mil for the time being. The web site is currently down, reportedly from being hacked by the Syrian Electronic Army."
The US and some of its allies have been supporting militants fighting against the government of Syrian President Bashar al-Assad since the crisis began in the Arab country back in 2011.
Moreover, the US military has been conducting airstrikes allegedly aimed at ISIL terrorists in Syria and neighboring Iraq since last year, despite which the Takfiris have gained ground in some of the regions.