A spokesman for Iran’s judiciary said on Sunday that around 100 suspects were arrested, following the recent attack on Saudi Arabia’s embassy in Tehran, The Associated Press (AP) reported.

The spokesman, Gholam Hossein Mohseni Ejehi, said the arrests took place after the January attacks. He did not give further details.

It is unusual for Iran to publicly announce arrests following such incidents, noted AP.

Protesters set fire to the Saudi embassy in Tehran and attacked its consulate in another Iranian city in response to the kingdom’s execution of prominent Shiite cleric Nimr al-Nimr on January 2.

Saudi Arabia severed ties with Iran following the protest, escalating tensions between the regional rivals.

Nimr was a driving force of the protests that broke out in 2011 in Eastern Province, where the Shiite minority of Saudi Arabia complains of marginalization.

He was arrested in 2012, with the Interior Ministry describing him as an “instigator of sedition”, before being executed earlier this month.

Before it announced the arrests, Iran had publicly expressed regret for the attack on the Saudi mission, saying it will spare no effort in arresting and prosecuting those responsible.