MANAMA, Bahrain, Jan. 20 (UPI) — Bahrain human rights activist Nabeel Rajab has been sentenced to six months in prison for tweets he posted last year.

Rajab was charged with insulting the Ministries of Interior and Defense.

In one of the tweets, he said the “ideological incubator” for men from Bahrain who became terrorists or joined the Islamic State were security institutions in the country.

The court maintained Rajab’s travel ban and set bail at $500 while he awaits the appeals process, if he chooses to pay.

Rajab helped found the Bahrain Center for Human Rights in 2002.

“Nabeel Rajab is being unjustly punished simply for posting tweets deemed insulting to the authorities,” according to Said Boumedouha, Deputy Director of Amnesty International‘s Middle East and North Africa Programme. “His conviction is a blow to freedom of expression — it must be quashed. He should be released immediately and unconditionally.”

One of Bahrain’s most prominent human rights activists, Nabeel Rajab, jailed for tweet http://t.co/GhC7Es5fiE pic.twitter.com/MvkcZv4oJi

— BBC Breaking News (@BBCBreaking) January 20, 2015