Mohsen Rezaei, secretary of Iran’s Supreme National Security Council, has warned neighbouring countries that their airports will also be affected if they side with the United States and prevent Iranian airlines from operating.

Speaking to Iranian state television on Wednesday, Rezaei told regional countries: “If you side with the United States, we will not stand by and watch.” He also warned that if they do not allow Iranian aircraft to operate, “your airports will have no flights”.

The remarks come amid mounting US pressure on Iran’s aviation industry. On September 8, the US Treasury Department added 27 Iranian airlines that had not previously been covered by the measures to its sanctions list.

The US Treasury Department has also said that foreign companies and institutions involved in certain transactions with, or providing services to, sanctioned individuals and companies could face secondary sanctions. Washington stepped up pressure to halt the operations of Iranian airlines from Wednesday, September 23, by threatening aviation service providers with secondary sanctions.