The Syrian Electronic Army, the pro President Bashar al-Assad hacking group, has compromised the website of the US Marines, replacing part of it with anti-American intervention messages and images.
It's the latest in a series of attacks by Syrian hackers, which have mostly focused on US media.
The US military recruitment website was replaced with what are supposedly images of American troops displaying messages including "I will NOT fight for Al Qaeda in Syria". Five images were accompanied by a "Message to the United States Marine corps", which labelled President Barack Obama "a traitor".
"This is a message writer by your brothers in the Syrian Army, who have been fighting Al Qaeda for the last three years. We understand your patriotism and love for your country so please understand our love for ours," said the statement posted to Marines.com.
"Obama is a traitor who wants to put your lives in danger to rescue Al Qaeda insurgents. Marines, please take a look at what your comrades think about Obama's alliance with Al Qaeda against Syria," it continued, above five images of individuals in military uniforms holding up anti-intervention messages.
"Your officer in charge probably has no qualms about sending you to die against soldiers just like you, fighting a vile common enemy. The Syrian army should be your ally not your enemy.
"Refuse your orders and concentrate on the real reason every soldier joins their military, to defend their homeland," the statement concluded.
The Marines website is now back to normal, with officials monitoring events in order to prevent any further cyber attacks. A Marines statement said the website itself hadn't been hacked, but users had been redirected away to the page.
Action against the Marines' website marks the latest incident in a string of attacks by the Syrian Electronic Army, which has also targeted media organisations including The New York Times and Channel 4 News.