Bahrain says authorities foiled possible attacks before the kingdom's Formula One race earlier this week, which was held under tight security amid a spike in anti-government unrest.
The Interior Ministry says a weapons cache, including 1,000 homemade firebombs, was found in a warehouse on Saturday, a day before the race.
The ministry also says two girls were arrested for allegedly plotting to carry out an attack.
The race went ahead without incident despite clashes in other parts of the island nation.
It's unclear why Bahrain waited until Tuesday to make the announcements, but it came while Gulf interior ministers met in Manama.
Bahrain has faced more than two years of unrest as majority Shiites seek a greater political voice in the Sunni-ruled nation.