Brazil dispatched extra police on Sunday to quell a strike by truckers opposing rising fuel and freight costs, after demonstrations turned violent.
Nearing its second week, the strike has hit 11 of Brazil's 26 states. The southern regions of Rio Grande do Sul, Parana and Santa Catarina have been hit especially hard.
One driver was killed when he was run over during a Saturday demonstration in Rio Grande do Sul as a lorry driver opposed to the action tried to break through a blockade.
"The federal government regrets the use of violence in the demonstrations, with vehicles looted and coercion against drivers who want to work," a statement from the presidential office read.
Extra police were being dispatched to ensure a court order passed last week forcing the strikers to end their action.
On Wednesday, the government indicated it would freeze diesel prices for six months in response to strikers' demands.
But Brasilia said the truckers would face heavy fines if they continued the stoppage that has slowed the delivery of foodstuffs in the continent-sized nation with almost nine million kilometers (5.6 million miles) of highways.
The protest has hit exports of goods including iron ore and soy, major earners for Brazilian export firms, with deliveries to ports severely delayed.