It was meant as a sardonic nudge to the president of Iran on his 55th birthday, DPA reported.
US State Department spokesman PJ Crowley tweeted a happy birthday greeting to Mahmoud Ahmadinejad Thursday, calling on him to release Americans Josh Fattal and Shane Bauer, the hikers arrested in July 2009, as a "gift."
He also told the Iranian leader that his 54th year had been "full of lost opportunities" and expressed his hope that Ahmadinejad's 55th year "would open Iran to a different relationship with the world."
Republican activist and Tea Party figure Sarah Palin jumped all over Crowley in her own tweet.
The former Alaska governor said Crowley's tweet was "cowtowing" and "coddling" the enemy because it had wished the Iranian leader a happy birthday. She said it represented US President Barack Obama's "mind-boggling foreign policy."
On Friday, Crowley shrugged off the incident.
"My tweet was simply to suggest that a reasonable celebration of President Ahmadinejad's birthday would be to release Shane Bauer and Josh Fattal," he told reporters.
"I can't imagine why Sarah Palin would object to the release of the two hikers who remain in custody, we think, inappropriately."