The fines and a warning to al-Ittihad stemmed from a match against Iran’s Foolad Mobarakeh Sepahan Esfahan, also known as Sephahan, the AFC said on its Twitter account on Friday, AFP reported.

Ittihad was fined $20,000 “because of what its fans had done to Sepahan,” the AFC said, without elaborating.

The Saudi club was also fined an additional $1,500 “for the tardiness of its team in entering the field,” AFC said, warning a repeat by Ittihad fans would mean the club having to play a match behind closed doors.

The incident between the Iranian and Saudi clubs coincided with ongoing political conflicts between the two countries.

Tensions ran high between Iran and Saudi Arabia after Riyadh’s execution of prominent Shiite cleric Sheikh Nimr al-Nimr, and a subsequent attack by outraged Iranian protesters on the Saudi embassy in Tehran, which resulted in the Arab country’s decision to sever its ties with the Islamic Republic.

On January 2, Saudi Arabia announced that it has executed Sheikh Nimr, among dozens of others. The execution ignited widespread international condemnation, from both political and religious figures.

The next day, furious demonstrators in the Iranian cities of Tehran and Mashhad stormed Saudi Arabia’s diplomatic buildings in protest at the execution of Sheikh Nimr.

Although Iranian officials criticized the embassy attack and police arrested dozens involved, Saudi Arabia cut off diplomatic relations with the Islamic Republic.