AFP reports that a mob protesting Saudi's execution of Sheikh Nimr al-Nimr, a top Shia cleric, attacked the Saudi embassy in Tehran and set the building on fire early Sunday morning.
"There are flames inside the embassy... demonstrators were able to get inside but have since been cleared out," the Iranian Student News Agency reported.
"The fire has destroyed the interior of the embassy," an eyewitness told AFP. "The police are everywhere and have dispersed the demonstrators, some of whom have been arrested."
Protesters climbed onto the roof of the embassy and pulled down the Saudi flag. Iranian police have secured the scene.
In Iran's second largest city Mashhad, protesters also set fire to the Saudi consulate.
These attacks on Saudi diplomatic buildings come in response to the execution of political dissident and Shia cleric Nimr al-Nimr, who spent over a decade studying theology in Iran. He was executed alongside 46 others in Saudi Arabia on Saturday for charges of "terrorism" and "incitement."
Shia-majority Iran has clashed with Sunni-majority Saudi Arabia on multiple occasions. According to AFP, Iranian government officials condemned the executions, stating that "the Saudi government supports terrorist movements and extremists, but confronts domestic critics with oppression and execution."
Saudi Arabia has summoned Iran's envoy to discuss the public statements and attacks on Saudi buildings in Iran.