"Oh my God, she's bleeding nonstop!" one person shouts. Another shouts: "Bandage it!"

Another video shows a woman being carried away in the aftermath as a blood trail can be seen on the ground. Those around her cry out that she has been shot by live ammunition in the leg.

Videos sent to the New York-based Center for Human Rights in Iran and later verified by The Associated Press show a crowd of demonstrators near Azadi, or Freedom, Square fleeing as a tear gas canister landed among them. People cough and sputter while trying to escape the fumes, with one woman calling out in Farsi: "They fired tear gas at people! Azadi Square. Death to the dictator!"

Iranian security forces fired both live ammunition and tear gas to disperse demonstrators protesting against the Islamic Republic's initial denial that it shot down a Ukrainian jetliner, online videos purported to show Monday.

Anti-government demonstrators wave an Iraqi national flag during a demonstration in Tahrir square, against the breach of Iraqi sovereignty by the U.S. and Iran.

Photos and video after the incident show pools of blood on the sidewalk.

Tehran's police chief, Gen. Hossein Rahimi, later denied his officers opened fire though the semiofficial Fars news agency said police "shot tear gas in some areas."

"Police treated people who had gathered with patience and tolerance," Iranian media quoted Rahimi as saying. "Police did not shoot in the gatherings since broad-mindedness and restraint has been agenda of the police forces of the capital."

However, uniformed police officers were just one arm of Iran's security forces who were out in force for the demonstrations.

Riot police in black uniforms and helmets gathered earlier Sunday in Vali-e Asr Square, at Tehran University and other landmarks. Revolutionary Guard members patrolled the city on motorbikes, and plainclothes security men were also out in force. People looked down as they walked briskly past police, apparently trying not to draw attention to themselves.

The Guard previously has been accused of opening fire on demonstrators during protests over government-set gasoline prices rising in November, violence that reportedly saw over 300 people killed.

Other videos from Fars showed demonstrators chanting: "We are children of war. Fight with us, we will fight back."

The crash of the Ukraine International Airline early on Wednesday killed all 176 people on board, mostly Iranians and Iranian-Canadians. After pointing to a technical failure and insisting for three days that the Iranian armed forces were not to blame, authorities on Saturday admitted accidentally shooting it down in the face of mounting evidence and accusations by Western leaders.

Iran downed the flight as it braced for possible American retaliation after firing ballistic missiles at two bases in Iraq housing U.S. forces earlier on Wednesday. The missile attack, which caused no casualties, was a response to the killing of Gen. Qassem Soleimani, Iran's top general, in a U.S. airstrike in Baghdad. But no retaliation came.

Iranians have expressed anger over the downing of the plane and the misleading explanations from senior officials in the wake of the tragedy. They are also mourning the dead, which included many young people who were studying abroad.

At earlier protests Saturday, students in Tehran shouted: "They are lying that our enemy is America! Our enemy is right here!" Another Fars video showed demonstrators on Sunday night tearing down a poster of Soleimani in Tehran.

Ali Rabiei, a government spokesman, insisted Iran's civilian officials only learned Friday that the Guard shot down the plane.

"The point is that we did not lie," Rabiei said. He went onto blame the U.S. for "spreading the shadow of war over Iran."

Javad Kashi, a professor of politics at Tehran Allameh University, wrote online that people should be allowed to express their anger in public protests. "Buckled under the pressure of humiliation and being ignored, people poured into the streets with so much anger," he wrote. "Let them cry as much as they want."

There's also been a cultural outpouring of grief and anger from Iran's creative community.

Some Iranian artists, including famed director Masoud Kimiai, withdrew from an upcoming international film festival. Two state TV hosts resigned in protest over the false reporting about the cause of the plane crash.

Taraneh Alidoosti, one of Iran's most-famous actresses, posted a picture of a black square on Instagram with the caption: "We are not citizens. We are hostages. Millions of hostages."

Saeed Maroof, the captain of Iran's national volleyball team, also wrote on Instagram: "I wish I could be hopeful that this was the last scene of the show of deceit and lack of wisdom of these incompetents but I still know it is not."

He said that despite the qualification of Iran's national team for the 2020 Tokyo Olympics after years of efforts, "there is no energy left in our sad and desperate souls to celebrate."

Meanwhile, another video making the rounds showed the national symbol of Iran, four crescents and a sword in the shape of a water lily flying through what appeared to be a 1980s-style video game like "Galaga." Music chimes when it touches oil as it fires on symbols representing people, knowledge and ultimately an airplane.

"To be continued," the caption at the end of the clip reads.