The US State Department was Wednesday under fire for spending $630,000 over two years to win millions of "likes" on its Facebook pages at a time of severe government austerity measures.

A scathing report by the department's independent watchdog took the coordinators of its social media outreach policy to task saying it needed to "direct its digital advertising to specific public diplomacy goals."

The report by the Office of the Inspector General found that two advertising campaigns launched in 2011 and 2012 cost some $630,000 with the "goal of building global outreach platforms for engagement with foreign audiences by increasing the number of fans... on four thematic Facebook properties."

"Many in the bureau criticize the advertising campaigns as 'buying fans' who may have once clicked on a post or 'liked' a photo but have no real interest in the topic and have never engaged further," read the report released late last month.

Although each of the four thematic pages run by the Bureau of International Information Programs managed to attract some 2.5 million fans by mid-March, only about 2 percent of those actually actively engaged with the sites by 'liking' topics or sharing information posted on it.

"Many postings had fewer than 100 comments or shares; the most popular ones had several hundred," the report said.

State Department spokeswoman Jen Psaki said the report had been taken seriously and vowed most its recommendations would be implemented before the start of the 2014 fiscal year in October.

"Online advertising has significantly decreased. It's now at $2,500 a month," she said, adding that "still allows us to reach out and communicate with a wide range of individuals living overseas."

The State Department has embraced the wide outreach made possible through social media, but is still developing guidelines for how such sites as Facebook and Twitter should be used in the world of diplomacy.