UPDATE 1-Shooting of Argentine lawmaker, aide was 'mafia style' - security minister

An Argentine lawmaker from the northern province of La Rioja was wounded on Thursday and an aide was killed in a shooting about a block from the National Congress in downtown Buenos Aires, in what the security minister described as a "mafia-style" attack.

Two attackers shot at Congressman Hector Olivares and his adviser, Miguel Yadon, early on Thursday. Yadon died at the scene and Olivares was in "serious condition" after undergoing surgery at a Buenos Aires hospital, officials said. "There is progress in the investigation. We believe the objective was Yadon, and they didn't want to kill," Security Minister Patricia Bullrich said at a press conference.

Bullrich rolled surveillance video of the attack, which appeared to show Yadon and Olivares fall to the ground after being shot. In the video, two people emerge from a nearby parked car and stay for a few moments at the scene before driving away. Authorities later located the car, she said. Bullrich said the "mafia-style" shooting was premeditated, but that the motive, and whether political or personal, was still unknown and is being investigated.

"We are going to go to great lengths to understand what happened and find the culprits," President Mauricio Macri said in a brief televised statement on Thursday. (Reporting by Walter Bianchi and Jorge Otaola; Writing by Cassandra Garrison; Editing by Jeffrey Benkoe and Susan Thomas)