"You [the United States] and your agents are the source of instability in the Middle East..."
Khamenei has made several statements denouncing the United States since the start of the Muslim holy month of Ramadan, while US President Donald Trump has spoken out against Iran in harsh terms since taking office, indicating that he will reverse the previous administration's attempts at rapprochement with Tehran.
Iranian Foreign Minister Mohammad Javad Zarif has accused Saudi Arabia of supporting terrorist groups inside Iran.
At an Arab Islamic American Summit in Riyadh last month, U.S. President Donald Trump accused Iran of fueling "the fires of sectarian conflict and terror" and called for its worldwide isolation.
"We believe that the rest of the global community will make it clear - as it has done already to them - that it considers the nuclear deal as a multilateral agreement and not a bilateral agreement between Iran and the United States", Zarif said.
Islamic State (IS) extremists claimed responsibility for the attacks, and Iranian officials have repeated accusations that Saudi Arabia funds Islamic militants, including IS.
The biggest diplomatic rift in years among the rich states of the Gulf has become a major test for the United States, which is closely allied to the countries on both sides. And it seems to elude many others in the West. If U.S. rates rise, Saudi Arabia is seen likely to follow suit with its rates because the country's currency is pegged to the dollar.
Tensions between Iran and Saudi Arabia have escalated further as Iran's Revolutionary Guards blamed the deadly June 7 attack in Tehran, which killed 17 people and wounded 52 others, on Saudi Arabia.
Iran's intelligence ministry said the attackers were Iranians who had joined ISIS in Iraq and Syria and returned home to carry out the attack.
"They did not come from Iran". And what if he is perceived to be already inside?