Bahrain placed three groups -- February 14 Coalition, Ashtar Brigades, and the Brigades of Resistance -- on its official terrorism list after a bomb detonated by a remote control device exploded Monday, killing three police officers.
Bahrain's national security was tested in 2011 by an uprising by the Shiite population. The Justice Ministry said Wednesday religious leaders were called on to issue edicts prohibiting support for terrorist groups, the official Bahrain News Agency reported.
U.N. Secretary-General Ban Ki-moon said Tuesday there was no justification for violence in Bahrain.
All Bahrainis, he said in a statement, are called on "to come together to create a conducive environment for promoting reconciliation."
Bahrain's human rights record has drawn criticism from groups like Human Rights Watch, who said the Sunni-led monarchy is trying to silence its critics.
Bahrain says it is committed to reforms recommended by an independent panel that probed the government's response to the Shiite-led uprising in 2011.