The ILNA labor news agency said thousands protested in the northwestern city of Tabriz and that police used teargas to try to disperse the crowd. The exact number of demonstrators could not be confirmed.
A resident said furious protesters threw stones at banks and smashed windows.
“They are angry because … we (Azeris) are insulted by a cartoon,” Soraya, a 40-year-old mother, told Reuters by telephone from Tabriz.
The cartoon, which appeared in Friday’s edition of the official Iran newspaper, showed a boy repeating the Persian word for cockroach in different ways, while a cockroach in front of the boy asked “What?” in Azeri.
The Azeris of northwestern Iran speak a language related to Turkish. Although Azeris have many luminaries among Iran’s commercial elite, Iran’s majority Persians mock them as stupid in their jokes.
The conservative Siyasat-e Rouz daily on Sunday said a crowd of Azeris had set fire to Iran’s local office in the city of Orumiyeh, where Azeris make up the majority of the population. They account for about 25 percent of the overall population.
ILNA said the protesters chanted slogans against the cartoon in Azeri outside the provincial governor’s office, which some of the crowd pelted with stones.
“The police are carrying out their responsibilities. The gathering in Tabriz is illegal,” an Interior Ministry official, identified only as Razavi, said, according to ILNA.
He added police were trying to restore order.
Earlier on Monday, some students at a university in Tehran also protested against the cartoon.
Some ethnic groups, including in Arab and Kurdish areas of Iran, have complained about unfair treatment from Tehran but the Azeri community usually has few complaints.
