Iran's supreme leader has accused Bahrain's Sunni-led government of "blatant foolishness and insanity" for stripping a prominent Shiite cleric of his citizenship.

Bahrain stripped Sheikh Isa Qassim of his citizenship this week, accusing him of fomenting sectarianism and forming groups that "follow foreign religious ideologies and political entities," an apparent reference to Shiite-majority Iran. The move sparked demonstrations by his supporters and outrage among Shiites across the region.

Ayatollah Ali Khamenei's website on Saturday quoted him as saying that the "persevering and knowledgeable" Qassim was a moderate who would have worked to "prevent extremist tactics." Khamenei says "now, no obstacle can prevent these young enthusiasts from rising up."

Bahrain crushed Arab Spring-inspired protests backed by majority Shiites against the Sunni monarchy in 2011, and has seen low-level unrest since then.