Police stand near the crime scene where Argentine lawmaker Hector Olivares was seriously injured and another man killed after they were shot at from a moving vehicle near the congressional building in Buenos Aire. Picture: Natacha Pisarenko/AP

Buenos Aires, Argentina - An Argentine lawmaker was seriously injured and another man was killed Thursday in one of the most brazen political attacks in the country since it returned to democracy in 1983.

Officials say that lawmaker Héctor Olivares was shot at around 7 am local time near the congressional building in the country's capital. Olivares is a representative of La Rioja province in Argentina's lower house of Congress. He is being treated at a hospital in Buenos Aires for gunshot wounds that pierced through his abdomen and affected vital organs.

The Telam state news agency identified the man who was killed as Miguel Marcelo Yadón, a coordinator who works in the fiduciary of federal electric transportation for La Rioja. Telam says that the men, who reportedly were friends since their teenage years, were shot at least six times. Argentine President Mauricio Macri said that doctors were trying to save Olivares' life and he expressed condolences to Yadón's family.

"We're moved by this attack," Macri said in a televised address. "We're praying for Héctor's life...We will do everything to find out what happened and find out who is guilty of this."

As Macri spoke, authorities wearing white jumpsuits collected evidence at the crime scene, where a tree had been pierced by bullets.

Hector Olivares attends a congressional commission session, in Buenos Aires. The Argentine lawmaker has been seriously injured and another man has been killed after they were shot at from a moving vehicle near the congressional building in the country's capital. File picture: Barbara Bancora/Nation's Honorable Chamber of Deputies, HCDN via AP

Local media had initially reported that Yadón and Olivares had been shot from a moving vehicle, but a video of the shooting released by the security ministry showed a parked car waiting for them. As the men walk by, they're shot at close range.

Yadón collapses on the sidewalk, while an injured Olivares tries to get up and holds up his arms in a desperate cry for help.

A burly man in the driver's seat then steps out of the car and paces around. Another man also steps out and walks away calmly, and when a police officer arrives on the scene, the car drives away slowly.

"We're going through a very sad and tough moment, especially because it confirms the presence of mafias in our country," Security Minister Patricia Bullrich said at a press conference.

"Yadón was killed from a car that was waiting for him....they shoot the main target, which was Yadón, they achieve murdering him, and having the opportunity to murder Olivares, they decide not to kill him."

Bullrich said that authorities found the car used in the crime and that they have identified the suspects, but would not release any information until they were captured.

Olivares belongs to the Radical Civic Union party of the ruling government coalition and is also part of the transportation committee in the lower house. Before he was shot, he had been discussing a bill against hooliganism in Argentine soccer, which produces some of the best players in the worked but is plagued by entrenched corruption and violence.

"If it does turn out that the judicial investigations show there is a connection to politically motivated violence then we can definitely say that we're facing a very grave institutional event," Olivares' spokesman, Ulises Bencina, told The Associated Press.

Attacks on politicians are unusual in Argentina, a country of about 44 million people, where the news usually centers on an ongoing economic crisis.

Politicians said the attack was the first of its kind since a brutal seven-year dictatorship from 1976-1983, during which thousands were killed, including some lawmakers.

AP