Earlier today Amnesty International tweeted a pointed comment on the civil unrest unfolding in the town of Ferguson, Missouri.
It wrote: "US can’t tell other countries to improve their records on policing and peaceful assembly if it won’t clean up its own human rights record."
Shortly before 7am, UK time, the influential Center for Strategic and International Studies, which describes itself as a public policy research institution "dedicated to analysis and policy impact", replied to Amnesty with the following tweet:
"@amnesty Your work has saved far fewer lives than American interventions. So, suck it."
Twitter watchers and followers of both accounts were stunned by the tone of the tweet.
Allen McDuffee, a journalist, tweeted: "Did this really just happen?" while Casey Martin quoted the think tank’s own literature to tweet: "If that’s not proof of '50 years of strategic insights and bipartisan policy solutions' then I don’t know what is."
CSIS was quick to launch a damage limitation exercise an hour later, after deleting the offending tweet, with an apology to Amnesty International via Twitter.
CSIS tweeted: "Our sincerest apologies to @Amnesty & our followers. Our last tweet was sent in error. We’re reviewing internal policies for social media."
A spokeswoman for Amnesty International told PR Week that "no offence was taken on its part" and that the human rights organisation "accepts the apology".
But Twitter reacted with a mixture of amusement and cynicism to the apology, with users joking about the fate of the person who sent out the tweet on behalf of CSIS.
But others, such as Patrick Davenne, were less amused.