Bahrain has ordered the acting Iranian charge d'affaires there to leave within 72 hours and will recall its own ambassador from the Islamic Republic over allegations it supports militant attacks in the tiny island kingdom.

The state-run Bahrain News Agency reported late Thursday that it had declared the Iranian diplomat "persona non grata." There was no immediate response from Iranian officials nor in the Islamic Republic's state-run media. The Sunni kingdom, which has faced four years of unrest from Shiite activists demanding more political freedom on the island, often accuses Iran of meddling in its internal affairs. It's not clear what specifically sparked Thursday's decision. Bahraini authorities announced late Wednesday they had seized 1.5 tons of explosives at a suspected militant hideout in a warehouse south of the capital, Manama.