BRASILIA, May 24 (Xinhua) -- Nationwide protests against fuel price hikes entered their fourth day on Thursday, sparking shortages of food and fuel supplies in some parts of the country.

Truck drivers demanding lower fuel taxes to compensate for liberalized gasoline prices continued to block highways in at least 15 states, disrupting deliveries of goods and cargo.

Supermarkets complained they were running low on produce, while five airports warned they only had enough fuel to operate through Thursday.

Airlines implemented contingency measures due to falling fuel reserves, several cities reduced the number of buses in circulation, and some industrial production was cutback.

Brazil's President Michel Temer held an emergency cabinet meeting early in the day with the president of the state oil firm Petrobras, Pedro Parente.

On Wednesday, in response to the protests, Petrobras lowered the price of diesel by 10 percent for a period of 15 days, while the Chamber of Deputies approved a proposal to scrap a tax on diesel through the end of this year. The bill next goes to the Senate.

However, the president of the Brazilian Truck Drivers Association (Abcam), Jose da Fonseca Lopes, said the roadblocks would remain in place until the government took a definitive step, such as publishing a reduction in the diesel tax in the Government Gazette.

Fonseca also criticized Petrobras' two-week measure, saying "it doesn't help", and called for an overhaul in the pricing policy.

Fuel costs account for 42 percent of their working expenses, drivers say, so lowering taxes would help counter the rise in gasoline and diesel prices since Petrobras liberalized prices, passing on to consumers any variations in the price of oil on the international market.

Truck drivers have given the administration until Friday to announce concrete measures, or "everything will come to a standstill."