Gunmen armed with automatic rifles and pistols have stormed a prison in Bahrain, killing a police officer and freeing 10 inmates convicted of terror offences.
The attack on Jaw prison is a significant escalation of the simmering unrest that has gripped the nation off the coast of Saudi Arabia since its 2011 Arab Spring protests.
No group immediately claimed responsibility for the attack, which sparked a manhunt across the island.
Confusion about the escape at the prison persisted for hours afterwards, as the Interior Ministry issued a series of tweets in Arabic and English contradicting each other.
Early on Monday morning the ministry issued a statement saying the attack was launched by "a terrorist cell of four to six members armed with automatic rifles and pistols".
It said the dead police officer was Abdulsalam Saif Ahmed and added that a second officer received moderate wounds in the attack.
People described stepped-up checkpoints across the country on Sunday, a day that also saw clashes between police and locals in the community of Sitra.
Bahrain hosts the US Navy's 5th Fleet and a British naval base is being built there.
The nation has seen low-level unrest since its 2011 Arab Spring protests, which saw the nation's Shiite majority and others demand more political freedom from the country's Sunni rulers.
The kingdom launched a wide-ranging crackdown on dissent in April, imprisoning some prominent political figures and forcing others into exile.
Activists, including imprisoned human rights advocate Nabeel Rajab, have claimed that Jaw has been the site of prisoner abuse.