"In the events of last night, unfortunately a total of about 10 people were killed in several cities," it said. At least 12 people have now died since protests began on Thursday.
On Monday, President Hassan Rouhani said the protests and criticism were an opportunity, not a threat.
He said the country should work together to fix its economic problems.
He said: "Our nation will deal with this minority who chant slogans against the law and people's wishes, and insult the sanctities and values of the revolution."