By Daniel Schweimler
BBC News, Buenos Aires
Argentina was brought to a near standstill on Monday amid protests over the killing of a teacher in the south-west of the country last week.
Thousands joined the protest in Buenos Aires
Tens of thousands took to the streets of Buenos Aires and other cities.
Schools closed, public transport was halted and banks and many offices shut for a couple of hours.
Carlos Fuentealba, a chemistry teacher, was killed during a protest over pay after being hit by a tear gas canister fired by police.
Public transport stopped for a couple hours on Monday and banks and some offices shut their doors in a protest called by the country's main trade union movement.
Mr Fuentealba,40, died after being hit on the head by a teargas canister fired by police during a protest in the south-western province of Neuquen.
He had joined his colleagues to demand a pay rise.
Clashes between provincial police and protesters are common around Argentina, but the killing of the popular, gentle family man, Carlos Fuentealba seems to have angered the nation.
The Neuquen governor has been a focus of protests
Protesters in Buenos Aires marched from the centre of the city, calling for the killers to be prosecuted and for the resignation of Neuquen province governor Jorge Sobisch who, they say, is responsible for police brutality.
The government of President Nestor Kirchner has so far kept quiet on the issue which seems to have struck a nerve in the Argentine population just months before the general election.