Human Rights Watch issued a letter to Bahrain's Attorney General Ali Fadhel al- Buainain expressing concern about the detention of human rights activist Yusuf al-Muhafadha, charged with "disseminating false news."
Bahrain since the start of the so-called Arab Spring in 2011 has been criticized for its human rights record. The government, however, maintains it's committed to reforms recommended by an independent commission of inquiry that probed a government crackdown on 2011 protests.
Joe Stork, deputy director of Middle East programs at Human Rights Watch, said Muhafadha has been jailed twice since November on dubious charges.
"If authorities pursue this questionable case, Muhafadha should be released pending trial," he said in a statement from Beirut.
The latest charges stem from pictures posted online of an activist allegedly injured by bird-shot pellets during protests in Manama.
Bahrain last year banned public demonstrations out of concern for national security. A U.N. envoy for abusive behavior is expected in the country in early spring.