Iran has summoned Bahrain's envoy to Tehran to protest a demonstration outside its embassy in Manama on the anniversary of a Shia uprising in the Gulf Arab kingdom, media reported.
"Iran has submitted an official protest to the Bahraini charge d'affaires over the gathering of a number of known people in front of the Iranian embassy in Manama who were shouting slogans against our nation's official," Iran's foreign ministry said in a quoted statement.
Iran said the protest was "unacceptable" and demanded the Bahraini government "prevent such actions."
The Bahraini envoy was summoned late Monday, the media reported.
Relations between Iran and Bahrain have been strained since February last year when the Gulf Arab country's Sunni regime clamped down on pro-democracy protests led by members of the majority Shia population.
Iran, which is predominantly Shia, has repeatedly condemned the crackdown and has criticised heavy sentences handed out to arrested protesters.
Bahraini police clashed with protesters on Monday, according to witnesses, on the anniversary of the uprising.
The Gulf kingdom remains in a political impasse, with Shia protesters back on the streets.
Activists have called for demonstrations to continue on Tuesday.