President Cristina Fernandez condemned the crime wave, saying it brought "shame to all Argentines," the Buenos Aires Herald reported.
"We have to ratify democracy against the violent and those who seek to install fear in the people," she said at a rally at Government House marking the 30th anniversary of the return to democracy to the South American country.
"I am not naive, I do not believe in coincidence nor in events that are contagious. Mumps, measles, rubella, these are contagious, but some of the things that happen in Argentina, on certain dates with certain leaders, are not. They are planned and executed, with military precision.
"These events are not coincidental because they seek to wear down the values of democracy."
Former Presidents Fernando de la Rua and Adolfo Rodriguez Saa attended the ceremony, as did Ricardo Alfonsin, son of his late namesake who was Argentina's first democratic leader following the military dictatorship of 1976-83, the Herald said.