A Washington, D.C., think tank apologized on Tuesday for telling the human rights group Amnesty International to “suck it” on Twitter.

Early Tuesday morning, Amnesty, which sent a delegation to observe the conflicts between protesters and police in Ferguson, Missouri, tweeted that the United States could not tell other nations to improve policing until it improved its own policing record. The Center for Strategic and International Studies responded by saying “your work has saved far fewer lives than American interventions. So. suck it.”

CSIS apologized for the tweet, which has since been deleted.

Our sincerest apologies to @Amnesty & our followers. Our last tweet was sent in error. We're reviewing internal policies for social media. — CSIS (@CSIS) August 19, 2014

CSIS spokesman Andrew Schwartz said an intern was to blame for the tweet, while adding that he was “embarrassed about this unfortunate situation and the tweet doesn't reflect anyone's views at CSIS or the institution as a whole.”

“It was sent by a CSIS intern who had access to our account for monitoring purposes," Schwartz said in an email to The Huffington Post. "Apparently he meant to send something reflecting his personal views from his personal Twitter account. I find his views and the way he expressed them to be abhorrent and am taking appropriate action at CSIS to address the matter internally.”

Schwartz also said that he had reached out to Amnesty to personally apologize but had been unsuccessful so far.