At least three people were reportedly shot dead when protesters attacked the Iranian consulate in the Iraqi holy city of Karbala on Sunday night.
The protesters, who demanded that Iran stop interfering in Iraq's internal affairs, climbed the consulate's walls.
There were reports that the security forces opened fire, but another account said unknown gunmen were responsible.
It came as mass demonstrations against Iraq's government continued in Baghdad despite a plea from the prime minister.
Adel Abdul Mahdi called on the protesters - who are angry at his failure to deal with widespread corruption, high unemployment and poor public services - to re-open roads and "help restore normality to the country".
He said the government respected peaceful protests, but that the blocking of roads around the capital and key ports in the south, combined with the "threatening of oil interests", had cost the country billions and contributed to price rises.
President Barham Saleh said last week that Mr Abdul Mahdi was willing to resign once a replacement was found, and that a new election law was being drafted.
But the protesters want to sweep away the entire political establishment.
BBC
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