Thousands of mainly Shia Muslim Bahrainis are in jail on charges of anti-government activities
Armed men attacked a prison in Bahrain on Sunday, freeing several convicts and killing a policeman, the interior ministry said.
"An armed attack on the Jau reform and rehabilitation centre resulted in the death of policeman Abdul Salam Saif and the escape of a number of inmates convicted of terrorist crimes," the ministry said in a statement.
The security forces launched a manhunt for the attackers and the escapees, the ministry said on Twitter.
Thousands of mainly Shia Muslim Bahrainis are in jail on charges ranging from participating in anti-government protests to armed attacks on security forces in the Western-allied Gulf kingdom, where the U.S. Fifth Fleet is based.
Bahrain has been rocked by unrest since its Sunni authorities crushed Shia-led protests in 2011 demanding a constitutional monarchy and an elected prime minister.
Hundreds of Shias have been arrested and many have faced trials over their role in the demonstrations.
Shia protesters continue to frequently clash with security forces in villages outside the capital Manama.