Saudi Arabia widened its rift with Iran on Monday, saying it would end air traffic and trade links with the Islamic republic and demanding that Tehran must "act like a normal country" before it would restore severed diplomatic relations.
Foreign Minister Adel al-Jubeir told Reuters in an interview that Tehran was responsible for rising tensions after the kingdom executed Shi'ite Muslim cleric Nimr al-Nimr on Saturday, describing him as a terrorist.
Insisting Riyadh would react to "Iranian aggression", he accused Tehran of dispatching fighters to Arab countries and plotting attacks inside the kingdom and its Gulf neighbours.
"There is no escalation on the part of Saudi Arabia. Our moves are all reactive.
It is the Iranians who went into Lebanon. It is the Iranians who sent their Qods Force and their Revolutionary Guards into Syria," Jubeir said.
Tehran says it has sent only military advisers to Syria and Iraq at their governments' requests, and denies plots in Gulf states.
The execution of Nimr provoked protests among Shi'ites across the region and Iranian protesters stormed the Saudi embassy in Tehran, setting fires and causing damage, prompting Riyadh to cut ties and inflaming an already heated rivalry.
"We will also be cutting off all air traffic to and from Iran.