UN Secretary-General Antonio Guterres urges the Iranian authorities to exercise maximum restraint and enable access to information in the country, his spokesperson said on Sunday.

"The Secretary-General urges the Iranian authorities to exercise maximum restraint and to refrain from unnecessary or disproportionate use of force," spokesperson Stephane Dujarric said in a statement.

He further urges steps that enable access to information in the country, including restoring communications, the statement reads.

Protests have erupted in several Iranian cities since late December over the sharp fall of the rial and long-standing economic hardship. Iranian authorities have acknowledged the demonstrations and voiced willingness to address economic grievances, while warning against violence and vandalism.

In a televised address on Friday, Iran's Supreme Leader Ali Khamenei urged people in Iran to preserve unity, saying that some protesters try to please the United States.

Deadly clashes have been reported between police and what the government described as "rioters" amid the ongoing protests. No official death toll has been released.