Bahrain said Iraqi Vice President Nuri Al Maliki's behaviour was "unacceptable" after a video emerged of the former Iraqi prime minister criticising Manama for an allegedly sectarian crackdown.
The Foreign Minister on Monday summoned the deputy charge d'affaires of the Iraqi embassy to denounce the statements made by Mr Al Maliki.
Mr Al Maliki, who now heads an Iraqi coalition called State of Law, attended a meeting last week organised by the February 14 movement, a Shia Bahraini activist group which Manama designated a terrorist group in 2014.
"Discrimination, marginalisation… have reached a severe limit on the people of Bahrain," Mr Al Maliki said, according to video from the event published by Iraqi media.
He was quoted as urging dialogue with those "demanding freedom and justice" to protect Bahrain and its people.
Bahrain barred the two main opposition groups from participating in November's parliamentary elections and arrested several members of its Shiite leadership.
Bahrain described Mr Maliki's statements as "blatant and unacceptable interference in the internal affairs of Bahrain," Bahrain's state news agency said.
[ Bahrain reports 67% turnout in parliamentary and municipal elections ]
[ US naval commander found dead in Bahrain home ]
[ RAK and Bahrain on upward trajectory, S&P says ]
An official in Bahrain's Foreign Minister described Mr Maliki’s attitude as "clear solidarity with those who seek to spread chaos, violence and terrorism and exhibit hatred," the agency reported.
Bahraini Undersecretary of Regional and GCC Affairs Wahid Mubarak Sayyar also rebuked the former Iraqi prime minister for his statements.
Bahrain's Shiite opposition groups claim social and political marginalisation led to unrest in recent years, in which demonstrators clashed with security forces. The Sunni-dominated government, in return, says the protests were sparked by interference from foreign entities, namely Qatar and Iran.
Iraq has struggled with Sunni-Shiite sectarianism since the 2003 US-led invasion, which led to a catastrophic war against ISIS. Critics of Mr Al Maliki say his policies during his eight-year tenure as prime minister helped fuel sectarianism.
Iraq's foreign ministry has not responded to the incident.
Bahrain is home to the US Navy’s Fifth Fleet, whose area of operations includes the Arabian Gulf and the Red Sea.