"Terrorists (were) arrested for plotting terrorist operations against security and civil peace," the interior ministry says on Twitter.
"Weapons and explosives from Iran
...a theocratic Shiite state divided among the Medes, the Persians, and the (Arab) Elamites....were seized" from group members who "are linked with terrorist groups in Iran," the brief statement says.
Sunni-ruled Bahrain accuses Shiite Iran of provoking unrest in the Gulf kingdom, an allegation Tehran denies.
The ministry gives no further details, including on how many people were arrested or their nationalities.
Bahrain has been hit by waves of unrest since 2011, when security forces crushed Shiite-led protests demanding a constitutional monarchy and an elected prime minister.
Opposition movements have been outlawed and hundreds of dissidents have been imprisoned — with many stripped of their nationality.
Human rights groups have frequently said cases against activists in Bahrain — men and women, religious and secular — fail to meet the basic standards of fair trials.
Bahrain’s authorities have repeatedly rejected the accusations.