By Phil Stewart

WASHINGTON, Jan 13 (Reuters) - If so-called "cyber jihadists" want to launch another social media attack on America's military, they will have plenty of targets: the U.S. Army alone lists more than 2,000 links to feeds on Facebook, Twitter, YouTube and other accounts.

In the wake of Monday's breach of U.S. Central Command's Twitter and YouTube feeds by apparent sympathizers of the Islamic State militant group, U.S. officials updated passwords and some distributed tip-sheets to help bolster online security.

But they showed no sign of shifting a social media strategy that has seen thousands of Facebook, Twitter and other accounts blossom as the world's most powerful military establishes an Internet presence that matches the global reach of its forces.

That large online profile carries unique risks for the military.

"It's their public face," said Ben FitzGerald at the Center for a New American Security think tank.

"So someone sitting in Baghdad isn't going to necessarily pick up the nuance that this is a non-military network and not a significant hack. So they're looking silly and they're looking weak."

The U.S. Department of Defense has "thousands and thousands" of social media accounts, said Colonel Steve Warren, a Pentagon spokesman. They are seen as a fast and effective way for the U.S. military to communicate with its own personnel and families about everything from on-base social events to power outages.

"We are certainly looking at our systems and will refine them as needed," said Warren.

Although a review of the incident was under way, he said, there had been no specific department-wide instructions issued since Monday to strengthen security across social media.

The Twitter and YouTube breach is far different than the one in 2008, when malware believed to have been crafted by a foreign intelligence service infiltrated Central Command's internal computer systems.

That attack was a dramatic illustration of the risks to military and defense-related networks critical to U.S. security, and triggered a massive expansion of cyber-defense efforts.

Monday's hack also did not lead to any theft or disclosure of classified information, officials said. But it delivered a highly symbolic blow by compromising the social media accounts of the military command overseeing sensitive operations in Iraq and Syria during a time of conflict.

It was a reminder of the perils of social media for an institution that prides itself on its vast security and image of unrivalled global power.

"WATCH YOUR BACK"

The hackers posted what officials said appeared to be authentic, but unclassified, rosters of current and retired top brass, including some private email addresses. They also posted messages, including: "American soldiers, we are coming, watch your back."