ISTANBUL

UN Secretary-General Antonio Guterres urged Iranian authorities Sunday to exercise "maximum restraint" and avoid "unnecessary or disproportionate" force against protesters.

"The Secretary-General is shocked by the reports of violence and excessive use of force by the Iranian authorities against protesters in multiple locations across the Islamic Republic of Iran, resulting in scores of deaths," spokesman Stephane Dujarric said in a statement.

Guterres emphasized all Iranians must be able to express their "grievances" peacefully without fear, stating rights to freedom of expression, association and peaceful assembly enshrined in international law must be "fully respected and protected."

The UN chief also called for steps enabling access to information in the country, including restoring communications.

London-based internet monitoring group NetBlocks said Sunday that Iran has been offline for over 72 hours as the country entered its fourth day of nationwide internet outage.

Protests erupted on Dec. 28 at Tehran's Grand Bazaar over the sharp depreciation of the Iranian rial and worsening economic conditions, later spreading to several cities.

US-based rights group HRANA reported deaths of 490 protesters and 48 security personnel, with more than 10,600 people arrested, though no official casualty estimates exist.