Reuters: A man accidentally blew himself up as he tried to plant a bomb targeting police in a Shi'ite Muslim village in Bahrain, the interior ministry said on Wednesday.

Several police officers have been killed over the past year in a series of attacks in the kingdom where discontent remains entrenched more than four years after mass protests by majority Shi'ites demanding reforms and a bigger role in government.

One officer was killed after a bomb went off near East Eker, south of the capital Manama, in July last year.

"Person killed himself in blast while trying to plant a bomb in East Eker. Bomb was meant to target police. Investigation opened," the ministry wrote on its Twitter feed.

The Sunni-ruled island, which hosts the U.S. Fifth Fleet, says it has made strides in political reform and is increasing monitoring for abuses by security forces.

Opponents and rights groups say abuses continue.

Bahrain freed prominent dissident Nabeel Rajab on health grounds on Tuesday, more than two months into his six-month jail term for insulting the authorities.