Héctor Olivares, representative of La Rioja province in Argentina's lower house of congress, was shot around 7 a.m. local time near the congressional building in Buenos Aires, officials said. He is being treated for gunshot wounds that pierced his abdomen and affected vital organs.
The dead man was identified by Telam state news agency as Miguel Marcelo Yadón, a coordinator who works in the fiduciary of La Rioja's federal electric transportation system. Telam says the men, who reportedly were friends since their teenage years, were shot at least six times.
Argentine President Mauricio Macri said 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. Local media initially reported that Yadón and Olivares had been shot from a moving vehicle, but a surveillance video of the shooting released by the security ministry showed a parked car waiting for them. As the men walk by, they're seen being 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. Another man also steps out and walks away calmly. When a police officer arrives on the scene, the car drives away slowly. Security Minister Patricia Bullrich said the shooting "confirms the presence of mafias in our country."
"Yadón was killed from a car that was waiting for him," Bullrich said in a press conference. "They shoot the main target, which was Yadón; they achieve his murder and having the opportunity to murder Olivares, they decide not to kill him."
Bullrich said authorities found the car used in the crime and have identified the suspects, but she said the motive has not been confirmed and is still being investigated. Local TV broadcast images late Thursday of federal police officers escorting a man suspected of having links to the attack from his apartment into a police car. His face was covered by a hood, and authorities did not release any other details.
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 world's best players but is plagued by entrenched corruption and violence.
"If it does turn out 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.
Associated Press journalists Paul Byrne and Mayra Pertossi contributed to this report.