The Twitter and YouTube accounts of the military's U.S. Central Command were taken over Monday by hackers claiming to be working on behalf of Islamic State militants.

American and coalition fighters are launching airstrikes against the group known as ISIS, or Islamic State in Iraq and Syria.

Canada is participating in the mission in Iraq by conducting airstrikes and helping to train Iraqi soldiers.

The first message on the hacked Twitter account appeared around 12:30 p.m. ET. "American soldiers, we are coming, watch your back," read one message. Other postings appeared to list names and phone numbers of military personnel as well as PowerPoint slides and maps.

A Central Command spokesperson confirmed Monday afternoon that Twitter and YouTube accounts had been compromised earlier in the day and said "appropriate measures" were being taken to address the issue.

An initial assessment indicated that no classified information was posted, the spokesperson said.

"This is little more than a prank or vandalism. It's inconvenient and it's an annoyance. But that's all it is," Col. Steve Warren, a Pentagon spokesman, told The Associated Press. "It in no way compromises our operations in any way, shape or form."

This screengrab shows messages that appeared in the U.S. Central Command's Twitter account on Monday morning. The account was suspended shortly afterwards and the White House says it is investigating. (Twitter.com)

Warren said Pentagon officials are in contact with Twitter and YouTube to ensure that military passwords and other security for such public websites are adequate

Shortly after the messages appeared, the @CENTCOM Twitter account was suspended along with the YouTube channel. Propaganda-style videos had been added to that account.

The sites — which are on commercial servers — were "compromised for approximately 30 minutes," but were kept offline while investigators looked into the incident, Central Command said in a statement Monday evening. As of 8:30 p.m. ET, the sites were still unavailable to the public.

The hackers titled the Central Command Twitter page "CyberCaliphate" with an underline that said "i love you isis." And the broader message referred to the ongoing airstrikes against ISIS and threatened, "We broke into your networks and personal devices and know everything about you. You'll see no mercy infidels. ISIS is already here, we are in your PCs, in each military base."

White House spokesman Josh Earnest told reporters that officials are looking into what happened and it is being taken seriously. He noted that Central Command's databases and website were not hacked, only social media website accounts.

White House examining incident

"There is a pretty significant difference between what is a large data breach and the hacking of a Twitter account," he said. "We're still examining and investigating the extent of this incident."

The hacker group could possibly be the same one that hijacked the websites or Twitter feeds of U.S. media outlets in the last month, including a Maryland television station and a New Mexico newspaper. The same logo, CyberCaliphate name and photo appeared on the Albuquerque Journal's website in late December when one of its stories was hacked. And earlier this month, it appeared that the same hackers breached the Journal's Twitter account and also took over the website and Twitter feed of WBOC-TV in Maryland.

The Central Command's area of responsibility includes Syria, Iraq, Afghanistan, and other countries in that region.

As news of the embarrassing hack emerged in Washington, President Barack Obama had just finished delivering a speech at the Federal Trade Commission on technology, privacy and data breaches.

Obama said identity theft is a growing problem that costs billions of dollars and can "ruin your life." He said the age of technology and digital innovation has created enormous vulnerabilities for the U.S. and cited the recent hack on Sony Pictures Entertainment as an example.

"This is a direct threat to the economic security of American families and we need to stop it," Obama said in a speech to the Federal Trade Commission. "If we are going to be connected, we need to be protected."

The White House said the hack did not represent a public relations victory for ISIS or its sympathizers. Earnest said, however, that it is still being taken seriously.

"This is something that will attract prominent attention in the administration, because this is something we take seriously," he told reporters.