In his first statements since the protests began last Thursday, Khamenei accused the country's enemies of "joining forces" against Iran and blamed them for the violence of the past few days.
The enemy is waiting for an opportunity, an imperfection, through which he can enter. Look at those events of the last days. All those who are against the Islamic Republic, those who have money, who have politics, who have weapons, those who have intelligence, have joined forces in order to create problems for the Islamic Republic and the Islamic Revolution. " , He said.
"God willing, I have things to say to my beloved people in due time. The hostility is here, but what can prevent this hostility is the spirit of courage, the spirit of sacrifice, the spirit of faith, a good example of what their children were, "he added.
Khamenei did not even clarify exactly who he was referring to, but Iranian President Hassan Rouhani earlier criticized US President Donald Trump for tweeting in favor of the protesters on Monday.
On Tuesday, Trump wrote another tweet, calling the Iranian government "brutal and corrupt."
"The people of Iran are finally acting against the brutal and corrupt regime of Iran. All the money that President Obama gave to them foolishly went to terrorism and went to their "pockets." People have little food, a lot of inflation and they do not have human rights. The United States is watching! ", Trump tweeted.
Other Iranian officials have blamed "outside agents" for the violence and an online "power war" waged by the United States, Britain and Saudi Arabia.
Khamenei's comments came after deadly violence on Monday in which nine people were killed, including seven protesters, a member of the pro-government militia and a policeman.
Another twelve died during the weekend as protests intensified.
The protests have become the biggest challenge to government authority since mass demonstrations in 2009. About 450 people have been arrested in the past three days, according to state media.