Blood was splattered on the streets of central Tehran late Sunday after pro-regime gunmen prowling the capital allegedly opened fire on anti-government protesters enraged over the downing of a passenger jet by nervous authorities.

The allegations of violence came as protests got under way for a third day in the capital and other cities following the Iranian regime’s startling admission on Saturday that it launched the missiles that downed Ukraine Airlines flight 752, killing all 176 aboard.

The destruction of the flight and the deaths of the mostly Iranian passengers have infuriated citizens across the political spectrum, many angry about the days of denial and obfuscation by senior military and government officials following the crash.

Many of those killed in the crash were young graduates of Iran’s most elite and prestigious educational institutions, heading back to promising jobs or research slots in the west following winter holidays with relatives. Profound grief rippled across the country.

“Oh! Oh! They killed Amir-Hossein! They killed Amir-Hossein!” the relatives of one plane crash victim screamed in despair in one Tehran neighbourhood, in a video posted online.

Video posted on Monday showed students, many under pressure to keep up with studies during exam time, gathering at Tehran’s Sharif University of Technology, demanding answers and accountability.

“They killed our elites, and they replaced them with mullahs,” they chanted.

“Resignation is not enough,” one of the protest leaders told The Independent. “We want prosecutions.”

Iran plane crash: Tehran admits accidentally shooting Boeing 737 Show all 25 1 /25 Iran plane crash: Tehran admits accidentally shooting Boeing 737 Iran plane crash: Tehran admits accidentally shooting Boeing 737 People standing and analysing the fragments and remains of the Ukraine International Airlines plane Boeing 737-800 that crashed outside the Iranian capital Tehran on January 8 National Security and Defense Council of Ukraine/AFP Iran plane crash: Tehran admits accidentally shooting Boeing 737 A hole in a part of Ukraine International Airlines Flight PS752 Iran said on January 11, it "unintentionally" shot down a Ukrainian passenger jet, killing all 176 people aboard, in an abrupt about-turn after initially denying Western claims it was struck by a missile Ukrainian Presidential Press Service/EPA Iran plane crash: Tehran admits accidentally shooting Boeing 737 Tehran Iranians protested in front of the Amir Kabir University in Tehran after the Iranian military released their statement about the flight EPA Iran plane crash: Tehran admits accidentally shooting Boeing 737 Debris of the wreckage Iranian president said a military probe into the tragedy had found "missiles fired due to human error" brought down the Boeing 737, calling it an "unforgivable mistake" National Security and Defense Council of Ukraine/AFP Iran plane crash: Tehran admits accidentally shooting Boeing 737 Tehran Local newspapers in Tehran carrying headlines such as: "National Mourning", "Apologize, Resign", "Unforgivable", "Great Disaster" ... concerning the downed Ukranian jetliner AFP via Getty Iran plane crash: Tehran admits accidentally shooting Boeing 737 Kiev, Ukraine Ukraine International Airlines President Yevhenii Dykhne stands next to a map of flight PS-752's departure path at a news briefing about the crash Reuters Iran plane crash: Tehran admits accidentally shooting Boeing 737 Tehran The Iranian students demonstrated following a tribute for the victims AFP via Getty Iran plane crash: Tehran admits accidentally shooting Boeing 737 The Canadian passport of a victim This handout photograph taken and released on January 11, 2019, by The National Security and Defense Council of Ukraine, shows the Canadian passport of avictim of the Ukraine International Airlines plane Boeing 737-800 that crashed outside the Iranian capital Tehran on January 8, 2020. - Iran said on January 11, 2020 it "unintentionally" shot down a Ukrainian passenger jet, killing all 176 people aboard, in an abrupt about-turn after initially denying Western claims it was struck by a missile. Iranian president said a military probe into the tragedy had found "missiles fired due to human error" brought down the Boeing 737, calling it an "unforgivable mistake". (Photo by STR / National Security and Defense Council of Ukraine / AFP) / RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / National Security and Defense Council of Ukraine" - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS (Photo by STR/National Security and Defense Co/AFP via Getty Images) STR National Security and Defense Council of Ukraine/AFP Iran plane crash: Tehran admits accidentally shooting Boeing 737 This combination of satellite pictures shows a before and after image of the crash site in Tehran The image (top), according to Maxar, shows vehicles and personnel (centre) during accident recovery and investigation on January 11, with a wall by the soccer pitch (left) destroyed as well as a wall (top right). The image below was taken on November 27, 2019 Maxar Technologies/AFP Iran plane crash: Tehran admits accidentally shooting Boeing 737 Ukraine The portraits of victims with flowers and candles at Boryspil International Airport in Kiev EPA Iran plane crash: Tehran admits accidentally shooting Boeing 737 Holes in the wreckage This handout photograph taken and released on January 11, 2019, by The National Security and Defense Council of Ukraine, shows holes in the wreckage of the Ukraine International Airlines plane Boeing 737-800 that crashed outside the Iranian capital Tehran on January 8, 2020. - Iran said on January 11, 2020 it "unintentionally" shot down a Ukrainian passenger jet, killing all 176 people aboard, in an abrupt about-turn after initially denying Western claims it was struck by a missile. Iranian president said a military probe into the tragedy had found "missiles fired due to human error" brought down the Boeing 737, calling it an "unforgivable mistake". (Photo by STR / National Security and Defense Council of Ukraine / AFP) / RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / National Security and Defense Council of Ukraine" - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS (Photo by STR/National Security and Defense Co/AFP via Getty Images) STR National Security and Defense Council of Ukraine/AFP Iran plane crash: Tehran admits accidentally shooting Boeing 737 Tehran People gathered for a candlelight vigil at the gate of Amri Kabir University AP Iran plane crash: Tehran admits accidentally shooting Boeing 737 People standing and analysing the fragments and remains of the Ukraine International Airlines plane This handout photograph taken and released on January 11, 2019, by The National Security and Defense Council of Ukraine, shows people standing and analysing the fragments and remains of the Ukraine International Airlines plane Boeing 737-800 that crashed outside the Iranian capital Tehran on January 8, 2020. - Iran said on January 11, 2020 it "unintentionally" shot down a Ukrainian passenger jet, killing all 176 people aboard, in an abrupt about-turn after initially denying Western claims it was struck by a missile. Iranian president said a military probe into the tragedy had found "missiles fired due to human error" brought down the Boeing 737, calling it an "unforgivable mistake". (Photo by STR / National Security and Defense Council of Ukraine / AFP) / RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / National Security and Defense Council of Ukraine" - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS (Photo by STR/National Security and Defense Co/AFP via Getty Images) STR National Security and Defense Council of Ukraine/AFP Iran plane crash: Tehran admits accidentally shooting Boeing 737 Protests against war with Iran took place in London The demonstration was co-organized by the Campaign For Nuclear Disarmament and the Stop the War Coalition, an activist group formed in 2001 Getty Iran plane crash: Tehran admits accidentally shooting Boeing 737 A hole in a part of Ukraine International Airlines Flight epa08119576 An undated handout picture provided by the Ukrainian Presidential Press Service allegedly shows a hole in a part of Ukraine International Airlines Flight PS752, issued on 11 January 2020. According to media reports on 11 January 2020, the Iranian military released a statement claiming that Ukraine International Airlines flight PS752 was shot down due to 'human error.' The Ukrainian jet, flying from Tehran, Iran, to Kiev, Ukraine, crashed minutes after takeoff on 08 January 2020, killing all 167 passengers and nine crew members aboard. EPA/UKRAINE PRESIDENTIAL PRESS SERVICE HANDOUT BEST QUALITY AVAILABLE HANDOUT EDITORIAL USE ONLY/NO SALES UKRAINE PRESIDENTIAL PRESS SERVICE HANDOUT Ukrainian Presidential Press Service/EPA Iran plane crash: Tehran admits accidentally shooting Boeing 737 Labour Party leader spoke at the event Jeremy Corbyn posing with an anti-war banner during the demonstration against the threat of war on Iran, in Trafalgar Square AFP via Getty Images Iran plane crash: Tehran admits accidentally shooting Boeing 737 A rose rests on a page featuring photographs of people who died in Iran Iranian Americans from across California converged in Los Angeles to participate in the California Convention for a Free Iran Reuters Iran plane crash: Tehran admits accidentally shooting Boeing 737 A young boy protests against a possible war with Iran in London A young protester at a Campaign for Nuclear Disarmament demonstration against a possible war with Iran in Trafalgar Square, central London. PA Photo. Picture date: Saturday January 11, 2020. See PA story POLITICS Iran. Photo credit should read: Jonathan Brady/PA Wire Jonathan Brady PA Iran plane crash: Tehran admits accidentally shooting Boeing 737 Holes in the wreckage This handout photograph taken and released on January 11, 2019, by The National Security and Defense Council of Ukraine, shows holes in the wreckage of the Ukraine International Airlines plane Boeing 737-800 that crashed outside the Iranian capital Tehran on January 8, 2020. - Iran said on January 11, 2020 it "unintentionally" shot down a Ukrainian passenger jet, killing all 176 people aboard, in an abrupt about-turn after initially denying Western claims it was struck by a missile. Iranian president said a military probe into the tragedy had found "missiles fired due to human error" brought down the Boeing 737, calling it an "unforgivable mistake". (Photo by STR / National Security and Defense Council of Ukraine / AFP) / RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / National Security and Defense Council of Ukraine" - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS (Photo by STR/National Security and Defense Co/AFP via Getty Images) STR National Security and Defense Council of Ukraine/AFP Iran plane crash: Tehran admits accidentally shooting Boeing 737 Rescue workers search the scene on January 8 In this Wednesday, Jan. 8, 2020, photo, rescue workers search the scene where a Ukrainian plane crashed in Shahedshahr, southwest of the capital Tehran, Iran. Iran on Saturday, Jan. 11, acknowledged that its armed forces "unintentionally" shot down the Ukrainian jetliner that crashed earlier this week, killing all 176 aboard, after the government had repeatedly denied Western accusations that it was responsible. (AP Photo/Ebrahim Noroozi) Ebrahim Noroozi AP Iran plane crash: Tehran admits accidentally shooting Boeing 737 Rescue workers search the scene In this Wednesday, Jan. 8, 2020 photo, rescue workers search the scene where a Ukrainian plane crashed in Shahedshahr, southwest of the capital Tehran, Iran. Iran on Saturday acknowledged that its armed forces "unintentionally" shot down the Ukrainian jetliner that crashed earlier this week, killing all 176 aboard, after the government had repeatedly denied Western accusations that it was responsible. (AP Photo/Ebrahim Noroozi) Ebrahim Noroozi AP Iran plane crash: Tehran admits accidentally shooting Boeing 737 Debris of the Ukraine International Airlines General view of the debris of the Ukraine International Airlines, flight PS752, Boeing 737-800 plane that crashed after take-off from Iran's Imam Khomeini airport, on the outskirts of Tehran, Iran January 8, 2020 is seen in this screen grab obtained from a social media video via REUTERS THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. MANDATORY CREDIT. SOCIAL MEDIA Reuters Iran plane crash: Tehran admits accidentally shooting Boeing 737 Debris of the Ukraine International Airlines (FILES) In this file photo taken on January 8, 2020 rescue teams are seen at the scene of a Ukrainian airliner that crashed shortly after take-off near Imam Khomeini airport in the Iranian capital Tehran. - Iran said on January 11 that it unintentionally shot down the Ukrainian plane due to 'human error'. (Photo by Akbar TAVAKOLI / IRNA / AFP) (Photo by AKBAR TAVAKOLI/IRNA/AFP via Getty Images) AKBAR TAVAKOLI IRNA/AFP/Getty Iran plane crash: Tehran admits accidentally shooting Boeing 737 One of the engines of the plane lies among the wreckage epa08118590 (FILE) - One of the engines of the plane lies among the wreckage after a Ukraine International Airlines Boeing 737-800 carrying 176 people crashed near Imam Khomeini Airport in Tehran, killing everyone on board, in Shahriar, Iran, 08 January 2020 (reissued 11 January 2020). According to media reports, the Iranian military released a statement on 11 January claiming that Ukraine International Airlines flight 752 was shot down due to a human error. EPA/ABEDIN TAHERKENAREH ABEDIN TAHERKENAREH EPA Iran plane crash: Tehran admits accidentally shooting Boeing 737 Debris of the Ukraine International Airlines FILE - In this Jan. 8, 2020, photo, debris is seen from an Ukrainian plane which crashed as authorities work at the scene in Shahedshahr, southwest of the capital Tehran, Iran. Iran announced Saturday, Jan. 11, that its military â€œunintentionallyâ€ shot down the Ukrainian jetliner that crashed earlier this week, killing all 176 aboard, after the government had repeatedly denied Western accusations that it was responsible. (AP Photo/Ebrahim Noroozi, File) Ebrahim Noroozi AP

The night before, pandemonium erupted in parts of central Tehran as protesters sought to seize control of Azadi Square, where only a week before mourners had commemorated Revolutionary Guard commander Qassem Soleimani.

It was his assassination in a US drone strike in Iraq, subsequent Iranian retaliation, and fears of US counterattack that prompted edgy Revolutionary Guard commanders to mistake the Ukraine Airlines Boeing 737 lumbering out of Tehran’s international airport on a routine flight path for an incoming US missile.

The downing of the jet shattered a rare moment of national unity in Iran, and reignited longstanding grievances that have resulted in on-and-off protests since late 2017.

The disaster has prompted Iran’s sole female Olympic gold-medal winner to defect to the west, a leading news anchor to resign and apologise for “lying to [Iranians] for 13 years,” and a major newspaper, Entekhab, to call for the resignation of Ali Shamkhani, secretary of the Supreme National Security Council.

In response, Iranian authorities appeared poised for a crackdown. The Council of Guardians, a body of ultra-conservative jurists who vet candidates for national office, announced that it had disqualified 90 sitting reformist lawmakers from running for office in 21 February elections citing “economic corruption, moral corruption, and contradicting the ruling establishment”.

Though they have yet to cut off the internet, as they did during November protests, Iranian censors blocked Entekhab, after it called for Mr Shamkhani’s departure. On the streets, they have deployed thousands of uniformed and plainclothes enforcers.

Video posted to the internet and distributed via the Telegram messaging app showed black-helmeted riot police beating protesters with batons near on a commercial street late Sunday.

“Don’t hit her! Don’t hit her!” a woman is heard yelling as a security enforcer in riot gear pummels a young couple.

In another clip, protesters crowd around what appears to be a bleeding protester, splotches of blood on a nearby pavement.

Other video showed gun-wielding regime militiamen, likely members of shadowy factions loyal to Supreme Leader Ali Khamenei, wielding assault rifles and scouring the streets in search of protesters. Witnesses said at least two people were shot and in unknown condition, even as the police denied using lethal force.

“The police did not fire shots during yesterday’s and today’s rallies ,” the newspaper Hamshahri, associated with the mayoralty of Tehran, quoted Brig-Gen Hossein Rahimi as saying.

Mr Rahimi claimed police had dealt with protesters “with restraint”. But he made no reference the often masked militiamen who serve as the regime’s shock troops.

Earlier on Sunday, pro-regime voices on television and on campuses warned that any violence would be the fault of peaceful protesters rather than the unaccountable pro-regime enforcers that often perpetrate violence.

In London, the Iranian ambassador was summoned to a meeting at the Foreign Office following the arrest of the UK’s top diplomat in Tehran on Saturday.

Rob Macaire, the UK’s ambassador to Iran, was detained for three hours by police over his “illegal and inappropriate” presence at a vigil for those killed in the downing of an Ukrainian plane, which had descended into protests.

Hamid Baeidinejad attended a meeting at the Foreign Office on Monday afternoon at which ministers conveyed their “strong objections” to the incident, which the UK claims breaches the Vienna Convention which governs diplomatic relations.

Dominic Raab, the foreign secretary, said the UK had demanded an apology for the “flagrant violation” of international law and said the security measures at the embassy in Tehran were being kept under review.

“The regime in Tehran is at a crossroads,” Mr Raab told MPs.