Policemen injured in blast on highway in Bahrain - interior ministry
Bahrain has been grappling with unrest by majority Shi'ite Muslims over the past three years demanding political reform and an end to what they see as discrimination.
They have staged regular protests as well as attacks on security forces using homemade bombs.
(Reporting By Farishta Saeed; Writing by Angus McDowall; Editing by Mark Heinrich)