A group of Iran demonstrators on Saturday demanded the country's Supreme Leader Ayatollah Ali Khamenei to step down as protests hit central Tehran after its military mistakenly shot down a Ukrainian plane, killing all 176 people on board last week.
"Commander-in-chief [Khamenei] resign, resign," videos posted on Twitter showed hundreds of people chanting in front of Tehran's Amir Kabir University.
Earlier on Saturday, Iran said its military had shot down the Ukrainian plane, calling it a "disastrous mistake".
The military claimed air defences were fired in error during an alert which was imposed after Iran missile struck US targets in Iraq.
Iran denied for days after Wednesday's crash that it brought down the plane, although a top Revolutionary Guards commander on Saturday said that he had told authorities about the "unintentional" missile strike the day it happened.
The Iran leadership had last faced mass protests in November following the rise in petrol prices.
The death of graduates from top universities migrating to Canada on the Ukrainian flight has struck a nerve with protesters. Many protesters felt their future is ruined in a country facing high unemployment.
The plane crash has further heightened international pressure on Iran after months of friction with the US and tit-for-tat attacks.
Khamenei, silent until now about the crash, said information should be made public, while top officials and the military issued apologies.
A US drone strike killed top Iran military commander Qasem Suleim in Iraq on January 3, prompting Tehran to fire at US targets on Wednesday.
Iran's Islamic Revolutionary Guards Corps (IRGC), in a rare step on Friday, apologised to the nation and accepted full responsibility for the plane crash. In a statement, the military said that the plane flew close to a sensitive Revolutionary Guards site at a time of high alert.
( With inputs from ANI )