More than five million passengers have been affected by the crackdown on smuggling by Chinese authorities, but at least one airline has announced that it will not fly to Iran.
The National Airlines of Iran said on Tuesday that it had cancelled more than 5.1 million flights to Iran from March 10 through May 4, citing security concerns.
The airline said it would suspend flights to Iraq and Saudi Arabia.
It said it has not yet received the orders to suspend flights from the other countries.
Iran has been a major transit route for people fleeing conflict in the Middle East and South Asia.
Iranian authorities have arrested more than 2,400 suspected drug traffickers in the past year and have arrested thousands more, including smugglers.