Two student demonstrators were shot dead on Thursday in Valparaiso, Chile, following the most recent protests calling for President Michelle Bachelet to deliver on promised educational reforms.

The two young men were shot by a 22-year-old resident, according to the Valparaiso police chief, Julio Pineda. It is unclear what provoked the altercation, but witnesses reported that the man became angry after the students placed propaganda on his property.

In a video of the altercation, the young men can be seen arguing with the shooter as a throng of people look on. The victims then run out of the camera frame, and two gunshots can be heard, followed by surprised whistles from the gathered crowd.

The victims were identified as Diego Guzman, 24, and Exequiel Borbaran, 18. Both were students at Chile's Santo Tomás University.

Borbaran and Guzman participated in the protest along with an estimated 160,000 others across the country, in a fresh bid to demand that Bachelet follow through with her second presidential campaign promise of free education for all of Chile's students.

"We condemn all violence, and regret the death of the two young men," Chile's interior minister Jorge Burgos said Thursday, adding that the government of Chile would be seeking justice for the two students.

Valentina Saavedra, president of the University of Chile's politically influential student government, also regretted the deaths, but was careful to keep the focus of the day's events on education reform.

"No one could have foreseen this. No one ever expects this sort of violence," Saavedra said during a press conference after the protests.

But, she added, "we want this government to stop its cronyism and begin the reforms."

Thursday's demonstrations spanned across several cities in Chile and were predominantly peaceful. However, disturbances led to the arrests of more than 150 people.

Demands for education reform in Chile, a promise included in Bachelet's 2013 presidential campaign, have recurred annually, as the reform is considered overdue. Protests are usually held just before Bachelet's annual congressional address on May 21.

Camila Vallejo, the former student leader and a current congresswoman with Chile's Communist party, also expressed concern over the violent turn. "I feel impotence, sadness, repugnance," Vallejo said Thursday on national television.

"The criminalization of social protests has led civilian citizens and carabineros" — Chilean police — "to value private property and order more than human lives," Vallejo tweeted.

The injured protesters were taken to a hospital in Valparaiso, where they were pronounced dead. According to Chile's National Police Director, Gustavo Gonzalez Jure, the suspected shooter is under arrest and has a prior criminal record.

Rodrigo Roman, a prominent public defender, said the suspect could face charges of first-degree murder, which in Chile is punishable by 15 to 20 years in prison.

"This regrettable and tragic act is a consequence of the politics of persecution of protesters," Roman told VICE News. "This is what leads a deranged person to take the lives of two young men. It is not an accident, it's a consequence."